229-786: Trident , also known as the Trident nuclear programme or Trident nuclear deterrent , covers the development, procurement and operation of nuclear weapons in the United Kingdom and their means of delivery. Its purpose as stated by the Ministry of Defence is to "deter the most extreme threats to our national security and way of life, which cannot be done by other means". Trident is an operational system of four Vanguard -class submarines armed with Trident II D-5 ballistic missiles , able to deliver thermonuclear warheads from multiple independently targetable re-entry vehicles (MIRVs). It
458-505: A cabinet sub-committee , the Gen 75 Committee (known informally by Attlee as the "Atomic Bomb Committee"), on 10 August 1945 to examine the feasibility of an independent British nuclear weapons programme. A nuclear reactor and plutonium-processing facility was approved by the Gen 75 committee on 18 December 1945 "with the highest urgency and importance". The Chiefs of Staff Committee considered
687-560: A circular error probable (CEP) accuracy to within "a few feet". It is guided using an inertial navigation system combined with a star tracker , and is not dependent on the American-run Global Positioning System (GPS). The 1998 Strategic Defence Review announced that the number of missile bodies would be limited to the 58 already purchased or under order, and the Royal Navy would not receive
916-470: A fractal surface, such as rocks or soil, and are used by navigation radars. A radar beam follows a linear path in vacuum but follows a somewhat curved path in atmosphere due to variation in the refractive index of air, which is called the radar horizon . Even when the beam is emitted parallel to the ground, the beam rises above the ground as the curvature of the Earth sinks below the horizon. Furthermore,
1145-424: A transmitter that emits radio waves known as radar signals in predetermined directions. When these signals contact an object they are usually reflected or scattered in many directions, although some of them will be absorbed and penetrate into the target. Radar signals are reflected especially well by materials of considerable electrical conductivity —such as most metals, seawater , and wet ground. This makes
1374-722: A British defence and security think tank , released a paper in July 2010 assessing four possible options for maintaining both an effective nuclear deterrent and also reducing costs in light of anticipated budget restrictions. These proposals were motivated by the fact that funding for the Trident renewal programme now had to come from the core Ministry of Defence budget. Four alternatives were considered: Trident submarines on continuous patrol; Trident submarines not on patrol continuously; attack submarines armed with nuclear cruise missiles; and land-based nuclear weapons. The paper concluded that "given
1603-429: A British goal, "the only existing safeguard against major aggression is the power to threaten retaliation with nuclear weapons." Churchill stated in a 1955 speech that deterrence would be "the parents of disarmament" and that, unless Britain contributed to Western deterrence with its own weapons, during a war the targets that threatened it the most might not be prioritised. The Prime Minister, Harold Macmillan , advanced
1832-543: A British member of the Combined Policy Committee from January 1947 to August 1948, left Americans with a distrust of British security arrangements. Most leading scientists and politicians of all parties were determined that Britain should have its own nuclear weapons. Their motives included national defence, a vision of a civil programme for nuclear power, and a desire that a British voice should be as powerful as any in international debate. Attlee set up
2061-699: A British representative, Penney watched the bombing of Nagasaki from the observation plane Big Stink . He also formed part of the Manhattan Project's post-war scientific mission to Hiroshima and Nagasaki that assessed the extent of the damage caused by the bombs. With the end of the war, the Special Relationship between Britain and the United States "became very much less special". The British government had trusted that America would share nuclear technology, which it considered
2290-700: A Combined Policy Committee meeting in June, the American copy could not be found. On 9 November 1945, Attlee and the Prime Minister of Canada , Mackenzie King , went to Washington, D.C., to confer with Truman about future cooperation in nuclear weapons and nuclear power. A Memorandum of Intention they signed replaced the Quebec Agreement. It made Canada a full partner, continued the Combined Policy Committee and Combined Development Trust, and reduced
2519-641: A Vickers Valiant piloted by Wing Commander Kenneth Hubbard , off the shore of Malden Island in the Pacific on 15 May 1957. It was Britain's second airdrop of a nuclear bomb after the Operation Buffalo test at Maralinga on 11 October 1956, and the first of a thermonuclear weapon. The United States had not attempted an airdrop of a hydrogen bomb until the Operation Redwing Cherokee test on 21 May 1956. Short Granite's yield
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#17327726815022748-596: A combined project. In November 1941, Frederick L. Hovde , the head of the London liaison office of the American Office of Scientific Research and Development (OSRD), raised the issue of cooperation and exchange of information with Anderson and Lord Cherwell , who demurred, ostensibly over concerns about American security. Ironically, it was the British project that had already been penetrated by atomic spies for
2977-627: A composite core which used both uranium-235 and plutonium. The bomb had a nominal yield of 15 kilotonnes of TNT (63 TJ). The cores were stored separately from the high explosive components in concrete "igloos" at RAF Barnham in Suffolk and RAF Faldingworth in Lincolnshire . Some casings were stored elsewhere in the UK and in Cyprus for "second strike" use. It remained in service until 1962, and
3206-558: A cone-shaped re-entry vehicle made in the US called the Mk 4 and is the same reentry vehicle used by the US Navy with its W76 warhead. This shell protects it from the high temperatures experienced upon re-entry into Earth's atmosphere. The Trident warhead's fusing, arming and firing mechanisms are carefully designed so that it can only detonate after launch and ballistic deployment. On 25 February 2020,
3435-566: A demonstration of the fact there are "credible and viable alternatives to the UK's current approach to nuclear deterrence." NGOs including the British American Security Information Council (BASIC), a non-proliferation and disarmament think-tank, criticised the report for its limited scope and its failure to engage with a wider array of considerations related to nuclear weapons, including environmental and humanitarian issues. Nuclear weapons and
3664-482: A different dielectric constant or diamagnetic constant from the first, the waves will reflect or scatter from the boundary between the materials. This means that a solid object in air or in a vacuum , or a significant change in atomic density between the object and what is surrounding it, will usually scatter radar (radio) waves from its surface. This is particularly true for electrically conductive materials such as metal and carbon fibre, making radar well-suited to
3893-663: A different form of the Teller-Ulam design to the Americans. The opposition that had derailed previous attempts was now absent. The McMahon Act was amended, paving the way for the 1958 US–UK Mutual Defence Agreement (MDA). Macmillan called this "the Great Prize". Under the MDA, 5.37 tonnes of UK-produced plutonium was sent to the US in exchange for 6.7 kg of tritium and 7.5 tonnes of HEU between 1960 and 1979. Much of
4122-620: A fifth submarine (allowing two to be on patrol at all times) was discussed, but ultimately rejected. Thatcher's popularity soared as a result of the British victory in the Falklands War , in which the ships that the Americans had insisted be retained played a crucial part. Trident's future was secured the following year when the Conservative Party won the 1983 general election , defeating a Labour Party that had pledged to cancel Trident. The first Trident boat, HMS Vanguard
4351-727: A former nuclear-armed aircraft bombardier-navigator and Staff Officer (Intelligence) to CINFLEET in the Falklands War; and Commander Colin Tabeart RN (Ret'd), a former Senior Engineer Officer on a Polaris submarine. Following this the MoD updated its online instruction notice to staff on public communications to say, “All contact with the media or communication in public by members of the armed forces and MoD civilians where this relates to defence or government business must be authorised in advance”. The Royal United Services Institute (RUSI),
4580-540: A full radar system, that he called a telemobiloscope . It operated on a 50 cm wavelength and the pulsed radar signal was created via a spark-gap. His system already used the classic antenna setup of horn antenna with parabolic reflector and was presented to German military officials in practical tests in Cologne and Rotterdam harbour but was rejected. In 1915, Robert Watson-Watt used radio technology to provide advance warning of thunderstorms to airmen and during
4809-529: A great nation, but if we continue to behave like a Great Power we shall soon cease to be a great nation. Let us take warning from the fate of the Great Powers of the past and not burst ourselves with pride." The government decided on 27 July 1954 to begin development of a thermonuclear bomb, and announced its plans in February 1955. British knowledge of thermonuclear weapons was based on the work done at
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#17327726815025038-494: A greater payload capacity. All three stages of the Trident II D-5 are made of graphite epoxy , making the missile much lighter than its predecessor. The first test from a British Vanguard -class submarine took place in 1994. The missile is 13 metres (43 ft) long, weighs 58.5 tonnes (129,000 lb), has a range of 11,300 kilometres (7,000 mi), a top speed of over 21,600 km/h (13,400 mph) (Mach 17.4) and
5267-596: A hillside at Coulport, 4 km (2.5 mi) to the west. Faslane was constructed and first used as a base during the Second World War. This location was chosen as the base for nuclear-armed submarines at the height of the Cold War because of its position close to the deep and easily navigable Firth of Clyde. It provides for rapid and stealthy access through the North Channel to the patrolling areas in
5496-602: A joint discovery. On 8 August 1945, the Prime Minister, Clement Attlee , sent a message to President Harry Truman in which he referred to themselves as "heads of the Governments which have control of this great force". But Roosevelt had died on 12 April 1945, and the Hyde Park Agreement was not binding on subsequent administrations. In fact, it was physically lost. When Wilson raised the matter in
5725-660: A large boosted fission weapon; Green Bamboo , an interim thermonuclear design similar to the Soviet Layer Cake used in Joe 4 and the American Alarm Clock; and Green Granite, a true thermonuclear design. The Green Granite prototype, known as Short Granite, was tested in the first of the Operation Grapple test series, Grapple 1. The bomb was dropped from a height of 45,000 feet (14,000 m) by
5954-526: A limited lifespan, and was expected to become obsolete by the 1990s. It was considered vital that an independent British deterrent could penetrate existing and future Soviet anti-ballistic missile (ABM) capabilities. An ABM system, the ABM-1 Galosh , defended Moscow, and NATO believed the USSR would continue to develop its effectiveness. The deterrent logic required the ability to threaten the destruction of
6183-518: A major loophole in the 1972 SALT I Agreement, which limited numbers of missiles but not warheads. During the SALT II negotiations the US had resisted Soviet proposals to include the British and French nuclear forces in the agreement, but there were concerns that supplying MIRV technology to the UK would be seen by the Soviets as violating the spirit of the non-circumvention clause in SALT II. Callaghan
6412-556: A matter of urgency, although it recognised that the resources required might be beyond those available to Britain. A new directorate known as Tube Alloys was created to coordinate this effort. Sir John Anderson , the Lord President of the Council , became the minister responsible, and Wallace Akers from Imperial Chemical Industries (ICI) was appointed the director of Tube Alloys. In July 1940, Britain had offered to give
6641-480: A megaton weapon. The bomb was hailed as a hydrogen bomb, and the truth that it was actually a large fission bomb was kept secret by the British government until the end of the Cold War . Penney cancelled the planned Green Granite test, and substituted Purple Granite, a Short Granite with some minor modifications. Its yield was a very disappointing 300 kilotonnes of TNT (1,300 TJ), even less than Short Granite;
6870-600: A metallic sphere of pure uranium-235 , and found that instead of tons, as everyone had assumed, as little as 1 to 10 kilograms (2.2 to 22.0 lb) would suffice, which would explode with the power of thousands of tons of dynamite. Oliphant took the resulting Frisch–Peierls memorandum to Sir Henry Tizard , the chairman of the Tizard Committee , and the MAUD Committee was established to investigate further. It held its first meeting on 10 April 1940, in
7099-607: A moratorium on nuclear testing. This did not mean an immediate end to testing; on the contrary, the United States, the Soviet Union and the United Kingdom all rushed to perform as much testing as possible before the deadline. A new British test series, known as Grapple Z, commenced on 22 August. It explored new technologies such as the use of external neutron initiators, which had first been tried out with Orange Herald. Core boosting using tritium and external boosting with layers of lithium deuteride were successfully tested, allowing
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7328-804: A new site at Aldermaston in Berkshire. Production facilities were constructed under the direction of Christopher Hinton , who established his headquarters in a former Royal Ordnance Factory (ROF) at ROF Risley in Lancashire . These included a uranium metal plant at Springfields , nuclear reactors and a plutonium processing plant at Windscale , and a gaseous diffusion uranium enrichment facility at Capenhurst , near Chester . The two Windscale reactors became operational in October 1950 and June 1951. The gaseous diffusion plant at Capenhurst began producing highly enriched uranium in 1954. Uranium ore
7557-749: A physics instructor at the Imperial Russian Navy school in Kronstadt , developed an apparatus using a coherer tube for detecting distant lightning strikes. The next year, he added a spark-gap transmitter . In 1897, while testing this equipment for communicating between two ships in the Baltic Sea , he took note of an interference beat caused by the passage of a third vessel. In his report, Popov wrote that this phenomenon might be used for detecting objects, but he did nothing more with this observation. The German inventor Christian Hülsmeyer
7786-403: A policy of nuclear disarmament, resulting in an ambiguous stance. While in office from 1964 to 1970 and 1974 to 1979, it built and maintained Polaris, and modernised it through the secret Chevaline programme. In opposition in the early 1980s, Labour adopted a policy of unilateral nuclear disarmament. More important than political differences was a shared sense of British national identity. Britain
8015-497: A possible successor might take up to 15 years to bring into service, depending on the nature of system chosen, and whether it was to be developed by the UK, or in collaboration with France or the US. With the recent experience of Chevaline in mind, the option of a purely British project was rejected. A study of the options was commissioned in February 1978 from a group chaired by the Deputy Under-Secretary of State at
8244-459: A pressure group, between 2000 and 2016 the vehicles were involved in 180 incidents, ranging from delays and diversions because of accidents, protests, or bad weather, to a sudden loss of power in one of the lorries, which halted a convoy and caused a double lane closure and a tailback on the M6 motorway . The group's analysis stated the incidents were more frequent in the years 2013–2015. Trident II D-5
8473-450: A proposal for further intensive research on radio-echo signals from moving targets to take place at NRL, where Taylor and Young were based at the time. Similarly, in the UK, L. S. Alder took out a secret provisional patent for Naval radar in 1928. W.A.S. Butement and P. E. Pollard developed a breadboard test unit, operating at 50 cm (600 MHz) and using pulsed modulation which gave successful laboratory results. In January 1931,
8702-732: A pulsed system, and the first such elementary apparatus was demonstrated in December 1934 by the American Robert M. Page , working at the Naval Research Laboratory . The following year, the United States Army successfully tested a primitive surface-to-surface radar to aim coastal battery searchlights at night. This design was followed by a pulsed system demonstrated in May 1935 by Rudolf Kühnhold and
8931-481: A quick decision is by launching a devastating attack upon [enemy cities] with absolute weapons." In 1947, the Chiefs of Staff stated that even with American help the United Kingdom could not prevent the "vastly superior" Soviet forces from overrunning Western Europe, from which Russia could destroy Britain with missiles without using atomic weapons. Only "the threat of large-scale damage from similar weapons" could prevent
9160-494: A real contribution to make to a 'merger.' Soon we shall have little or none." The British considered producing an atomic bomb without American help, but it would require overwhelming priority, would disrupt other wartime projects, and was unlikely to be ready in time to affect the outcome of the war in Europe . The unanimous response was that before embarking on this, another effort should be made to secure American cooperation. At
9389-442: A rescue. For similar reasons, objects intended to avoid detection will not have inside corners or surfaces and edges perpendicular to likely detection directions, which leads to "odd" looking stealth aircraft . These precautions do not totally eliminate reflection because of diffraction , especially at longer wavelengths. Half wavelength long wires or strips of conducting material, such as chaff , are very reflective but do not direct
Trident (UK nuclear programme) - Misplaced Pages Continue
9618-486: A safe on board each of the Vanguard -class submarines. If contact with the UK is lost, the commanding officer of a submarine has to follow the instructions in the letter if they believe that the United Kingdom has suffered an overwhelming attack. Options include retaliating with nuclear weapons, not retaliating, putting the submarine under the command of an ally or acting as the captain deems appropriate. The exact content of
9847-473: A smaller, lighter two-stage devices. The international moratorium commenced on 31 October 1958, and Britain ceased atmospheric testing for good. Believing that the United Kingdom was extremely vulnerable to a nuclear attack to which defence was impossible, the Chiefs of Staff and the RAF first advocated a British nuclear deterrence—not just nuclear weapons—in 1945: "It is our opinion that our only chance of securing
10076-503: A special consultant. Because the Quebec Agreement specified that nuclear weapons would not be used against another country without mutual consent, British authorisation was required for their use. On 4 July 1945, Field Marshal Henry Maitland Wilson agreed that the use of nuclear weapons against Japan would be recorded as a decision of the Combined Policy Committee. Along with Group Captain Leonard Cheshire , sent by Wilson as
10305-677: A system might do, Wilkins recalled the earlier report about aircraft causing radio interference. This revelation led to the Daventry Experiment of 26 February 1935, using a powerful BBC shortwave transmitter as the source and their GPO receiver setup in a field while a bomber flew around the site. When the plane was clearly detected, Hugh Dowding , the Air Member for Supply and Research , was very impressed with their system's potential and funds were immediately provided for further operational development. Watson-Watt's team patented
10534-424: A transmitting antenna , a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving information about the objects' locations and speeds. Radar was developed secretly for military use by several countries in
10763-514: A wide region and direct fighter aircraft towards targets. Marine radars are used to measure the bearing and distance of ships to prevent collision with other ships, to navigate, and to fix their position at sea when within range of shore or other fixed references such as islands, buoys, and lightships. In port or in harbour, vessel traffic service radar systems are used to monitor and regulate ship movements in busy waters. Meteorologists use radar to monitor precipitation and wind. It has become
10992-843: A writeup on the apparatus was entered in the Inventions Book maintained by the Royal Engineers. This is the first official record in Great Britain of the technology that was used in coastal defence and was incorporated into Chain Home as Chain Home (low) . Before the Second World War , researchers in the United Kingdom, France , Germany , Italy , Japan , the Netherlands , the Soviet Union , and
11221-456: A year later, and rallies for unilateral nuclear disarmament in London in October 1981 and June 1982 attracted 250,000 marchers, the largest ever mass demonstrations in the UK up to that time. The 1982 Labour Party Conference adopted a platform calling for the removal of the GLCMs, the scrapping of Polaris and the cancellation of Trident. This was reaffirmed by the 1986 conference. While the party
11450-452: Is a simplification for transmission in a vacuum without interference. The propagation factor accounts for the effects of multipath and shadowing and depends on the details of the environment. In a real-world situation, pathloss effects are also considered. Frequency shift is caused by motion that changes the number of wavelengths between the reflector and the radar. This can degrade or enhance radar performance depending upon how it affects
11679-590: Is a submarine-launched ballistic missile built by Lockheed Martin Space Systems in Sunnyvale, California , and deployed by the US Navy and the Royal Navy. The British government contributed five per cent of its research and development costs under the modified Polaris Sales Agreement. The development contract was issued in October 1983, and the first launch occurred in January 1987. The first submarine launch
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#173277268150211908-451: Is as follows, where F D {\displaystyle F_{D}} is Doppler frequency, F T {\displaystyle F_{T}} is transmit frequency, V R {\displaystyle V_{R}} is radial velocity, and C {\displaystyle C} is the speed of light: Passive radar is applicable to electronic countermeasures and radio astronomy as follows: Only
12137-614: Is based on the system used on the American Ohio class , although with capacity for only 16 missiles, rather than the 24 on board an Ohio boat. The boats are significantly larger than the Resolution class, and were given names formerly associated with battleships and aircraft carriers, befitting their status as capital ships . An important consideration was the depth of the Walney Channel , which connected Barrow to
12366-567: Is intended. Radar relies on its own transmissions rather than light from the Sun or the Moon, or from electromagnetic waves emitted by the target objects themselves, such as infrared radiation (heat). This process of directing artificial radio waves towards objects is called illumination , although radio waves are invisible to the human eye as well as optical cameras. If electromagnetic waves travelling through one material meet another material, having
12595-401: Is operated by the Royal Navy and based at Clyde Naval Base on the west coast of Scotland. At least one submarine is always on patrol to provide a continuous at-sea capability. The missiles are manufactured in the United States, while the warheads are British. The British government initially negotiated with the Carter administration for the purchase of the Trident I C-4 missile. In 1981,
12824-417: Is the range. This yields: This shows that the received power declines as the fourth power of the range, which means that the received power from distant targets is relatively very small. Additional filtering and pulse integration modifies the radar equation slightly for pulse-Doppler radar performance , which can be used to increase detection range and reduce transmit power. The equation above with F = 1
13053-421: Is unclear, but Britain refused because of its intention to develop its own weapons. By that year, international control of atomic weapons seemed almost impossible to achieve, and Truman proposed to the Joint Committee on Atomic Energy in July a "full partnership" with Britain in exchange for uranium; negotiations between the two countries began that month. While the first Soviet atomic bomb test in August 1949
13282-414: Is usually undergoing maintenance and the remaining two are in port or on training exercises. During a patrol, the submarine is required to remain silent and is allowed to make contact with the UK only in an emergency. It navigates using mapped contour lines of the ocean floor and patrols a series of planned "boxes" measuring several thousand square miles. A 1,000-metre-long (3,300 ft) aerial trails on
13511-438: The Air Ministry had abandoned the concept of a conventional defence of Western Europe. The hydrogen bomb increased the threat to Britain. In 1957, a government study stated that although RAF fighters would "unquestionably be able to take a heavy toll of enemy bombers, a proportion would inevitably get through. Even if it were only a dozen, they could with megaton bombs inflict widespread devastation." Although disarmament remained
13740-404: The Blue Danube free-fall bomb. It had a 60-inch (1,500 mm) diameter, 32 explosive lens implosion system with a levitated pit suspended within a natural uranium tamper . The warhead was contained within a bomb casing measuring 62 inches (1,600 mm) diameter and 24 feet (7.3 m) long, and it weighed approximately 4.5 tonnes (4.4 long tons), of which about 2.5 tonnes (2.5 long tons)
13969-404: The British Ambassador to the United States , Sir Oliver Wright , and the US Secretary of State , George Shultz . The Trident programme was projected to cost £5 billion, including the four submarines, the missiles, new facilities at Coulport and Faslane and the contribution to Trident II D-5 R&D. It was expected to absorb 5 per cent of the defence budget. As with Polaris, the option for
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#173277268150214198-515: The British Army of the Rhine , were withdrawn in July 1992. The British Conservative government followed suit. The deployment of ships carrying nuclear weapons caused embarrassment during the Falklands War, and in the aftermath it was decided to stockpile them ashore in peacetime. The nuclear depth bombs were withdrawn from service in 1992, followed by the WE.177 free-fall bombs used by the Royal Navy and RAF on 31 March 1998. This left Trident as Britain's sole nuclear weapons system. Although Trident
14427-428: The Foreign Office , Sir Antony Duff , with the Chief Scientific Adviser to the Ministry of Defence , Sir Ronald Mason . The Duff-Mason Report was delivered to the Prime Minister, James Callaghan , in parts on 11 and 15 December. It recommended the purchase of the American Trident I C-4 missile then in service with the US Navy. The C-4 had multiple independently targetable re-entry vehicle (MIRV) capability, which
14656-420: The Irish Sea , which limited the draft to 27 + 1 ⁄ 2 feet (8.4 m), while the Ohio -class boats had a draft of 33 feet (10 m). Each boat is 150 metres (490 ft) long and 13 metres (43 ft) in diameter, and carries a crew of 150 officers and ratings. The submarines use a tactical-information and weapons-control system called the Submarine Command System Next Generation . This system
14885-407: The Los Alamos Laboratory was headed by Chadwick, and later Peierls. It included distinguished scientists such as Geoffrey Taylor , James Tuck , Niels Bohr , William Penney , Frisch, Ernest Titterton and Klaus Fuchs , who was later revealed to be a Soviet spy. As overall head of the British Mission, Chadwick forged a close and successful partnership with Brigadier General Leslie R. Groves ,
15114-411: The Monte Bello Islands in Australia in Operation Hurricane . Eleven more British nuclear weapons tests in Australia were carried out over the following decade, including seven British nuclear tests at Maralinga in 1956 and 1957. The British hydrogen bomb programme demonstrated Britain's ability to produce thermonuclear weapons in the Operation Grapple nuclear tests in the Pacific, and led to
15343-574: The Nyquist frequency , since the returned frequency otherwise cannot be distinguished from shifting of a harmonic frequency above or below, thus requiring: Or when substituting with F D {\displaystyle F_{D}} : As an example, a Doppler weather radar with a pulse rate of 2 kHz and transmit frequency of 1 GHz can reliably measure weather speed up to at most 150 m/s (340 mph), thus cannot reliably determine radial velocity of aircraft moving 1,000 m/s (2,200 mph). In all electromagnetic radiation ,
15572-506: The Quebec Conference in August 1943, Churchill and the President of the United States , Franklin Roosevelt , signed the Quebec Agreement , which merged the two national projects. The Quebec Agreement established the Combined Policy Committee and the Combined Development Trust to coordinate their efforts, and specified that the weapons could only be used if both the US and UK governments agreed. The 19 September 1944 Hyde Park Agreement extended both commercial and military cooperation into
15801-669: The RAF's Pathfinder . The information provided by radar includes the bearing and range (and therefore position) of the object from the radar scanner. It is thus used in many different fields where the need for such positioning is crucial. The first use of radar was for military purposes: to locate air, ground and sea targets. This evolved in the civilian field into applications for aircraft, ships, and automobiles. In aviation , aircraft can be equipped with radar devices that warn of aircraft or other obstacles in or approaching their path, display weather information, and give accurate altitude readings. The first commercial device fitted to aircraft
16030-405: The Reagan administration announced its decision to upgrade its Trident to the new Trident II D-5 missile. This necessitated another round of negotiations and concessions. The UK Trident programme was announced in July 1980 and patrols began in December 1994. Trident replaced the submarine-based Polaris system, in operation from 1968 until 1996. Trident is the only nuclear weapon system operated by
16259-419: The Secretary of State of the United States as I have just been in my discussion with Mr Byrnes . We've got to have this thing over here, whatever it costs ... We've got to have the bloody Union Jack flying on top of it." The decision to proceed was formally made on 8 January 1947 at a meeting of Gen 163, a subcommittee of the Gen 75 Committee consisting of six Cabinet members, including Attlee, and
16488-494: The Soviet Union . The United Kingdom did not have the manpower or resources of the United States, and despite its early and promising start, Tube Alloys fell behind its American counterpart and was dwarfed by it. On 30 July 1942, Anderson advised the Prime Minister of the United Kingdom , Winston Churchill , saying: "We must face the fact that ... [our] pioneering work ... is a dwindling asset and that, unless we capitalise it quickly, we shall be outstripped. We now have
16717-771: The Sputnik crisis , facilitated the amendment of the McMahon Act, and the 1958 US–UK Mutual Defence Agreement (MDA), which allowed Britain to acquire nuclear weapons systems from the US, thereby restoring the nuclear Special Relationship . During the 1950s, Britain's nuclear deterrent was based around the V-bombers of the Royal Air Force (RAF), but developments in radar and surface-to-air missiles made it clear that bombers were becoming increasingly vulnerable, and would be unlikely to penetrate Soviet airspace by
16946-459: The Trident has been the only operational nuclear weapons system in British service. The delivery system consists of four Vanguard -class submarines based at HMNB Clyde in Scotland. Each submarine is armed with up to sixteen Trident II missiles , each carrying warheads in up to eight multiple independently targetable re-entry vehicles (MIRVs). With at least one submarine always on patrol,
17175-594: The United States Atomic Energy Act of 1946 (McMahon Act) ended technical co-operation. Fearing a resurgence of US isolationism , and losing its own great power status, the British government resumed its own development effort . The first British atomic bomb was tested in Operation Hurricane on 3 October 1952. The subsequent British development of the hydrogen bomb , and a fortuitous international relations climate created by
17404-670: The United States Atomic Energy Commission 's Lewis Strauss and Senator Arthur Vandenberg , did not. Their opposition, along with security concerns raised by the arrest of Fuchs, who was working at Harwell, ended the negotiations in January 1950. After Britain developed nuclear weapons through its own efforts, the engineer Sir Leonard Owen stated that "the McMahon Act was probably one of the best things that happened ... as it made us work and think for ourselves along independent lines." Churchill, now again prime minister, announced on 17 February 1952 that
17633-468: The University of Birmingham , were tasked with carrying out a series of experiments on uranium. Oliphant delegated the task to two German refugee scientists, Rudolf Peierls and Frisch, who ironically could not work on the university's secret projects like radar because they were enemy aliens and therefore lacked the necessary security clearance. In March 1940 they calculated the critical mass of
17862-884: The Vanguards perform a strategic deterrence role and also have a sub-strategic capability. The neutron was discovered by James Chadwick at the Cavendish Laboratory at the University of Cambridge in February 1932, and in April 1932, his Cavendish colleagues John Cockcroft and Ernest Walton split lithium atoms with accelerated protons . In December 1938, Otto Hahn and Fritz Strassmann at Hahn's laboratory in Berlin-Dahlem bombarded uranium with slow neutrons, and discovered that barium had been produced. Hahn wrote to his colleague Lise Meitner , who, with her nephew Otto Frisch , determined that
18091-440: The electromagnetic spectrum . One example is lidar , which uses predominantly infrared light from lasers rather than radio waves. With the emergence of driverless vehicles, radar is expected to assist the automated platform to monitor its environment, thus preventing unwanted incidents. As early as 1886, German physicist Heinrich Hertz showed that radio waves could be reflected from solid objects. In 1895, Alexander Popov ,
18320-407: The reflective surfaces . A corner reflector consists of three flat surfaces meeting like the inside corner of a cube. The structure will reflect waves entering its opening directly back to the source. They are commonly used as radar reflectors to make otherwise difficult-to-detect objects easier to detect. Corner reflectors on boats, for example, make them more detectable to avoid collision or during
18549-534: The "new boy" Arnold Frederic Wilkins to conduct an extensive review of available shortwave units. Wilkins would select a General Post Office model after noting its manual's description of a "fading" effect (the common term for interference at the time) when aircraft flew overhead. By placing a transmitter and receiver on opposite sides of the Potomac River in 1922, U.S. Navy researchers A. Hoyt Taylor and Leo C. Young discovered that ships passing through
18778-413: The 1920s went on to lead the U.K. research establishment to make many advances using radio techniques, including the probing of the ionosphere and the detection of lightning at long distances. Through his lightning experiments, Watson-Watt became an expert on the use of radio direction finding before turning his inquiry to shortwave transmission. Requiring a suitable receiver for such studies, he told
19007-772: The 1950s and 1960s, which was known as V force of the Main Force. The three V bombers were the Vickers Valiant , which entered service in February 1955; the Avro Vulcan , which entered service in May 1956; and the Handley Page Victor , which entered service in November 1957. The V Bomber force reached its peak in June 1964, when 50 Valiants, 70 Vulcans and 39 Victors were in service. A month after Britain's first atomic weapons test, America tested
19236-751: The Air Staff, was appointed the Controller of Production, Atomic Energy (CPAE) in March 1946. The Gen 75 Committee considered the proposal in October 1946. In October 1946, Attlee called a meeting to discuss building a gaseous diffusion plant for uranium enrichment . Michael Perrin , who was present, later recalled that: The meeting was about to decide against it on grounds of cost, when [Ernest] Bevin arrived late and said "We've got to have this thing. I don't mind it for myself, but I don't want any other Foreign Secretary of this country to be talked at or to by
19465-702: The American government cancelled Skybolt. John F. Kennedy , then President of the United States, and Harold Macmillan , then UK Prime Minister, negotiated the Nassau Agreement , under which the US would sell Polaris systems for UK-built submarines. This was formalised in the Polaris Sales Agreement . The first British Polaris ballistic missile submarine (SSBN), HMS Resolution , was laid down by Vickers-Armstrongs at its yard at Barrow-in-Furness in Cumbria on 26 February 1964. She
19694-442: The American observers into thinking they were thermonuclear explosions, as they were involved in their analysis. The next test was Grapple 2, of Orange Herald, the first British weapon to incorporate an external neutron initiator . It was dropped on 31 May, and exploded with a force of 720 to 800 kilotonnes of TNT (3,000 to 3,300 TJ). The yield was the largest ever achieved by a single stage device, which made it technically
19923-589: The Bertrand Russell Peace Foundation which stated, “It is completely unacceptable that the UK continues to spend billions of pounds on deploying and modernising the Trident Nuclear Weapon System when faced with the threats to health, climate change and world economies that Coronavirus poses.” Signatories included Commander Robert Forsyth RN (Ret'd), a former nuclear submariner; Commander Robert Green RN (Ret'd),
20152-408: The British nuclear weapons projects of the 1950s, and postponed, but did not avert, Polaris's obsolescence. The Conservative Party had a strong pro-defence stance, and supported the British nuclear weapons programme, although not necessarily at the expense of conventional weapons. The rival Labour Party had initiated the acquisition of nuclear weapons, but in the late 1950s its left wing pushed for
20381-470: The Duff-Mason report, but had been rejected, as its additional capability—the extended range from 4,000 to 6,000 nautical miles (7,400 to 11,100 km)—was not required by the UK, and it was more expensive. Exactly how much more expensive was uncertain, as it was still under development. At the same time, the British government was well aware of the costs of not having the same hardware as the US. Nor did
20610-528: The HEU supplied by the US was used not for weapons, but as fuel for the growing fleet of UK nuclear submarines . Under the MDA, the US supplied the UK with not just nuclear submarine propulsion technology, but a complete S5W pressurised water reactor of the kind used to power the US Skipjack -class submarines. This was used in the Royal Navy's first nuclear-powered submarine, HMS Dreadnought , which
20839-617: The Los Alamos Laboratory during the war. Two British scientists, Egon Bretscher and Klaus Fuchs, had attended the conference there on the Super (as it was then called) in April 1946, and Chadwick had written a secret report on it in May 1946, but the design was found to be unworkable. Some intelligence about Joe 4 was derived from its debris, which was provided to Britain under the 1948 Modus Vivendi . Penney established three megaton bomb projects at Aldermaston: Orange Herald ,
21068-658: The MISC 7 cabinet committee formally approved the decision to purchase C-4 the following day. When Thatcher met with Carter again on 17 December, he still asked for more time, but the Soviet invasion of Afghanistan on 24 December ended all hope of Senate ratification of SALT II, clearing the way for the sale to proceed. The British government hoped that Trident could be secured on the same terms as Polaris, but when its chief negotiator, Robert Wade-Gery , sat down with his American counterpart, David L. Aaron , in March 1980, he found this
21297-605: The Mark 7 or Red Beard. They too were assigned to the SACEUR in October 1960. The planned V-bomber force was reduced to 144 aircraft, and it was intended to equip half of them with Project E weapons, so 72 Mark 5 nuclear bombs were supplied for the V-bombers. When the MDA came into force, the US agreed to supply the V-bombers with megaton weapons in place of the Mark 5, in the form of Mark 15 and Mark 39 nuclear bombs . Under
21526-682: The North Atlantic, and through the GIUK gap between Iceland and Scotland to the Norwegian Sea . Also based there are Astute -class nuclear-powered fleet submarines (SSNs). RNAD Coulport is used to store the nuclear warheads and has docking facilities where they are loaded onto submarines before going on patrol and unloaded when they return to the base. Repair and refit of the Vanguard -class submarines takes place at HMNB Devonport near Plymouth , Devon. According to senior RAF officers
21755-582: The Project E MOU, US personnel had custody of the weapons. This meant they performed all the tasks related to their storage, maintenance and readiness. The bombs were stored in Secure Storage Areas (SSAs) on the same bases as the bombers which British staff were not permitted to enter. It was therefore impossible to store British and American bombs together in the same SSA. US custody also created operational problems. The procedure for handing over
21984-406: The RAF. They became operational on 3 April 2020. The Campaign for Nuclear Disarmament (CND) was a national movement founded in the late 1950s, initially in opposition to nuclear testing. It reached its peak around 1960, by which time it had evolved into a broader movement calling for Britain to unilaterally give up nuclear weapons, withdraw from NATO, and end the basing of nuclear-armed aircraft in
22213-711: The Rapier batteries, and an expansion of the US base on Diego Garcia , which had assumed great importance since the Soviet invasion of Afghanistan. The Secretary of State for Defence , Francis Pym , informed Cabinet of the decision to purchase Trident on 15 July 1980, and announced it in the House of Commons later that day. The agreement was effected by amending the Polaris Sales Agreement, changing "Polaris" to "Trident". However, on 4 November 1980, Ronald Reagan
22442-559: The Reagan administration promise to sell D-5 on the same terms as the C-4. To pay for Trident, the British government announced deep cuts to other defence spending on 25 June 1981. Negotiations commenced on 8 February, with the British team again led by Wade-Gery. The Americans were disturbed at the proposed British defence cuts, and pressed for an undertaking that the aircraft carrier HMS Invincible be retained in service, which they felt
22671-486: The Rhine with nuclear weapons under Project E in the form of aerial bombs, missiles, depth charges and artillery shells until 1992. Nuclear-capable American aircraft had been based in the UK since 1949, but the last US nuclear weapons were withdrawn in 2008. In 1982, the Polaris Sales Agreement was amended to allow the UK to purchase Trident II missiles. Since 1998, when the UK decommissioned its tactical WE.177 bombs,
22900-427: The Royal Navy, at least one submarine has always been on patrol ever since. In British service, Trident II missiles are fitted with a thermonuclear warhead called Holbrook. The warhead has a choice of two warhead yields the highest of which is thought to be 100 kilotons of TNT (420 TJ), with a lower yield in the range of 0.3 to 10 kilotons of TNT (1.3 to 41.8 TJ). The UK government was sensitive to charges that
23129-561: The Secretary of State for Defence, Malcolm Rifkind , announced that each boat would deploy no more than 96 warheads. In 2010 this was reduced to a maximum of 40 warheads, split between eight missiles. The consequent reduction in warhead production and refurbishment was estimated to save £22 million over a ten-year period. However in 2021 the Prime Minister Boris Johnson announced that the total number of warheads
23358-524: The Soviet Union from using atomic weapons in a war. Air Chief Marshal Sir John Slessor , who became Chief of the Air Staff in 1950, wrote that year that the Soviet superiority in European forces was so great that even "an ultimatum by Russia within the next two to three years" might cause Western Europe to surrender without a war. He feared that the United Kingdom might also do so "unless we can make ourselves far less defenceless than we are now." By 1952,
23587-400: The Soviet capital and other major cities. To ensure that a credible and independent nuclear deterrent was maintained, the UK developed an improved warhead package Chevaline , which replaced one of the three warheads in a Polaris missile with multiple decoys, chaff , and other defensive countermeasures . Chevaline was extremely expensive; it encountered many of the same issues that had affected
23816-440: The Trident programme was £9.8 billion, about 38 per cent of which was incurred in the US. In 2005–06, annual expenditure for the running and capital costs was estimated at between £1.2 billion and £1.7 billion and was estimated to rise to £2bn to £2.2 billion in 2007–08, including Atomic Weapons Establishment costs. Since Trident became operational in 1994, annual expenditure has ranged between 3 and 4.5 per cent of
24045-418: The Trident system was intended to "pose a potential threat to key aspects of Soviet state power" whilst being invulnerable to a surprise or pre-emptive nuclear strike . As with Polaris, Trident was owned and operated by the UK but committed to NATO and targeted in accordance with plans set out by the organisation's Supreme Allied Commander Europe , who is traditionally a senior figure in the US military. Under
24274-520: The UK Government announced that "the UK will move to an overall nuclear weapon stockpile of no more than 260 warheads." British SSBNs on patrol carried a maximum of 40 warheads and 8 missiles. In 2011 it was reported that British warheads would receive the new Mk 4A reentry vehicles and some or all of the other upgrades that US W76 warheads were receiving in their W76-1 Life Extension Program. Some reports suggested that British warheads would receive
24503-488: The UK could accept a "significant increase in vulnerability" and a reduction in who it could deter. The publication of the report was met with a mixed reception from different political parties and non-governmental organisations (NGOs) in the field of non-proliferation and disarmament. While it was welcomed by the prime minister, David Cameron , as having confirmed the necessity of like-for-like replacement of Trident, Liberal Democrat cabinet minister Danny Alexander deemed it
24732-461: The UK is allowed to draw upon US warhead design information, but constructing and maintaining warheads for the Trident programme is the responsibility of AWE. US President George H. W. Bush authorised the transfer of nuclear warhead components to the UK between 1991 and 1996. The first Holbrook warhead was finished in September 1992 with production probably ending in 1999. Each warhead is housed in
24961-534: The UK released a Written Statement outlining that the current UK nuclear warheads will be replaced and will match the US Trident SLBM and related systems. Earlier, it was reported that Commander US Strategic Command, Admiral Charles Richard, mentioned in a Senate hearing that the UK was already working to replace its warheads, matching the future US W93 warhead. As of 2016, the UK had a stockpile of 215 warheads, of which 120 are operationally available. In 2022
25190-411: The UK since the decommissioning of tactical WE.177 free-fall bombs in 1998. NATO 's military posture was relaxed after the collapse of the Soviet Union in 1991. Trident warheads have never been aimed at specific targets on an operational patrol, but await co-ordinates that can be programmed into their computers and fired with several days' notice. Although Trident was designed as a strategic deterrent,
25419-578: The UK would not use or threaten to use nuclear weapons against any non-nuclear weapon party to the Treaty on the Non-Proliferation of Nuclear Weapons 1968 , but only if the state is not in "material breach" of the Treaty's obligations. The shift in language comes after the UK lifted the cap on the number of Trident nuclear warheads it can stockpile by 40% from 180 to 260 warheads "in recognition of
25648-450: The UK would reserve the right to use nuclear weapons in the face of weapons of mass destruction , which includes "emerging technologies that could have a considerable impact", including cyber technologies, to chemical or biological weapons. This marks a shift from existing UK policy, in that nuclear weapons would only be launched against another nuclear power or in response to extreme chemical or biological threats. It did, however, stress that
25877-418: The UK would use nuclear weapons in a " pre-emptive initial strike " in "the most extreme circumstances". Fallon stated in a parliamentary answer that the UK has neither a 'first use' or 'no first use' in its nuclear weapon policy so that its adversaries would not know when the UK would launch nuclear strikes. In March 2021, the UK suggested a shift in nuclear policy in its Integrated Defence Review, stating that
26106-578: The UK. The end of atmospheric nuclear testing, internal squabbles, and activists focusing their energies on other causes led to a rapid decline, but it revived in the early 1980s in the wake of the Thatcher government's December 1979 decision to allow the deployment of GLCMs in the UK under the NATO Double-Track Decision , and the announcement of the decision to purchase Trident in July 1980. Membership leapt from 3,000 in 1980 to 50,000
26335-438: The US and USSR. While the military target of British nuclear weapons was the Soviet Union, the political target was the United States. Independent targeting was vital. The Chiefs of Staff believed that—contrary to Tizard's view—once the Soviet Union became able to attack the United States itself with nuclear weapons in the late 1950s, America might not risk its own cities to defend Europe, or not emphasise targets that endangered
26564-551: The US to do so, but for that the Carter administration wanted undertakings that the UK would raise defence spending by the same amount, or pay the cost of US forces manning Rapier batteries and Ground Launched Cruise Missile (GLCM) sites in the UK. On 2 June 1980, Thatcher and the US Secretary of Defense, Harold Brown , agreed to $ 2.5 billion for the C-4 missile system, plus a 5 per cent R&D levy, British personnel for
26793-417: The US. The US would maintain and support the missiles, while the UK would manufacture its own submarines and warheads to go on the missiles. The warheads and missiles would be mated in the UK. This was projected to save about £500 million over eight years at Coulport, while the Americans spent $ 70 million upgrading the facilities at Kings Bay. The sale agreement was formally signed on 19 October 1982 by
27022-410: The US. While Britain would not formally give up building or researching its own weapons, the US would manufacture all the bombs and allocate some to Britain. By agreeing to subsume its own weapons programme within the American one, the plan would have given Britain nuclear weapons much sooner than its own target date of late 1952. Although Truman supported the proposal, several key officials, including
27251-408: The USSR obtaining British atomic technology after conquering the United Kingdom in an invasion of western Europe. In February 1949 General Dwight D. Eisenhower offered to General Sir William Duthie Morgan American atomic weapons if the British programme ended. Britain would have used the weapons with its own aircraft for its own targets . Whether the McMahon Act would have permitted the transaction
27480-672: The United Kingdom In 1952, the United Kingdom became the third country (after the United States and the Soviet Union ) to develop and test nuclear weapons , and is one of the five nuclear-weapon states under the Treaty on the Non-Proliferation of Nuclear Weapons . The UK initiated a nuclear weapons programme, codenamed Tube Alloys , during the Second World War. At the Quebec Conference in August 1943, it
27709-600: The United Kingdom more than the United States. Britain thus needed the ability to convince the USSR that attacking Europe would be too costly regardless of American participation. Part of the perceived effectiveness of an independent deterrent was the willingness to target enemy cities. Slessor saw atomic weapons as a way to avoid a third devastating world war given that the two previous ones had begun without them. When Air Marshal Sir George Mills became head of RAF Bomber Command in 1955 he similarly insisted on targeting Soviet cities. The Soviet Union's launch of Sputnik 1 ,
27938-668: The United States access to its scientific research, and the Tizard Mission 's John Cockcroft briefed American scientists on British developments. He discovered that the American S-1 Project (later renamed the Manhattan Project ) was smaller than the British, and not as far advanced. The British and American projects exchanged information, but did not initially combine their efforts. British officials did not reply to an August 1941 American offer to create
28167-513: The United States were denied access to papers that they had written just days before. This partly resulted from the arrest for espionage of British physicist Alan Nunn May , who had worked in the Montreal Laboratory, in February 1946, while the legislation was being debated. It was but the first of a series of spy scandals. The arrest of Klaus Fuchs in January 1950, and the June 1951 defection of Donald Maclean , who had served as
28396-724: The United States, independently and in great secrecy, developed technologies that led to the modern version of radar. Australia, Canada, New Zealand, and South Africa followed prewar Great Britain's radar development, Hungary and Sweden generated its radar technology during the war. In France in 1934, following systematic studies on the split-anode magnetron , the research branch of the Compagnie générale de la télégraphie sans fil (CSF) headed by Maurice Ponte with Henri Gutton, Sylvain Berline and M. Hugon, began developing an obstacle-locating radio apparatus, aspects of which were installed on
28625-418: The amendment of the McMahon Act. Since the 1958 US–UK Mutual Defence Agreement , the US and the UK have cooperated extensively on nuclear security matters. The nuclear Special Relationship between the two countries has involved the exchange of classified scientific data and fissile materials such as uranium-235 and plutonium . The UK has not had a programme to develop an independent delivery system since
28854-419: The amount of highly enriched uranium to be reduced from 120 to 75 kg. Its yield was estimated at 0.5 megatonnes of TNT (2.1 PJ). For use in the V bombers, it was placed in a Blue Danube casing to become Violet Club . Road transport of the weapon was hazardous. As a safety measure 120,000 steel ball bearings were used to fill a cavity inside the core and keep the fissile components apart. In an accident,
29083-432: The annual defence budget, and was projected to increase to 5.5 per cent of the defence budget by 2007–08. An important factor in the cost was the exchange rate between the dollar and the pound, which declined from $ 2.36 in September 1980 to $ 1.78 in March 1982. The principle of Trident's operation is known as Continuous At-Sea Deterrence (CASD), which means that at least one submarine is always on patrol. Another submarine
29312-486: The arrest of Oshchepkov and his subsequent gulag sentence. In total, only 607 Redut stations were produced during the war. The first Russian airborne radar, Gneiss-2 , entered into service in June 1943 on Pe-2 dive bombers. More than 230 Gneiss-2 stations were produced by the end of 1944. The French and Soviet systems, however, featured continuous-wave operation that did not provide the full performance ultimately synonymous with modern radar systems. Full radar evolved as
29541-443: The basing of the Trident system close to Glasgow, Scotland's largest city. Some members and ex-members of those parties, such as Tommy Sheridan and Lloyd Quinan , have taken part in blockades of the base. For a major House of Commons vote in 2007, the majority of Scottish members of parliament (MPs) voted against upgrading the system, while a substantial majority of English and Welsh MPs voted in favour. The house backed plans to renew
29770-479: The beam path caused the received signal to fade in and out. Taylor submitted a report, suggesting that this phenomenon might be used to detect the presence of ships in low visibility, but the Navy did not immediately continue the work. Eight years later, Lawrence A. Hyland at the Naval Research Laboratory (NRL) observed similar fading effects from passing aircraft; this revelation led to a patent application as well as
29999-421: The boats to deploy Type 2066 and Type 2071 decoys, and a UAP Mark 3 electronic support measures (ESM) intercept system is carried. A "Core H" reactor is fitted to each of the boats during their long-overhaul refit periods, ensuring that none of the submarines will need further re-fuelling. Thatcher laid the keel of the first boat, HMS Vanguard , on 3 September 1986, and it was commissioned on 14 August 1993. She
30228-523: The bombs added an extra ten minutes to the bombers' reaction time, and the requirement that US personnel had guardianship of the weapons at all times meant that neither they nor the bombers could be relocated to dispersal airfields as the RAF desired. The operational restrictions imposed by Project E "effectively handed the US government a veto over the use of half of Britain's nuclear deterrent". The Air Council decided on 7 July 1960 that Project E weapons would be phased out by December 1962, by which time it
30457-471: The cancellation of the Blue Streak in 1960. Instead, it purchased US delivery systems for UK use, fitting them with warheads designed and manufactured by the UK's Atomic Weapons Establishment (AWE) and its predecessor. Under the 1963 Polaris Sales Agreement , the US supplied the UK with Polaris missiles and nuclear submarine technology. The US also supplied the Royal Air Force and British Army of
30686-475: The changes had not worked. An Operational Requirement (OR1142) was issued in 1955 for a thermonuclear warhead for a medium-range ballistic missile , which became Blue Streak . This was revised in November 1955, with "megaton" replacing "thermonuclear". Orange Herald could then meet the requirement. Codenamed Green Grass , the unsuccessful fusion boosting was omitted, and it used Green Bamboo's 72-lens implosion system instead of Orange Herald's 32. This allowed
30915-399: The choice of yield for the warheads on its Trident missiles". The UK has not declared a no first use policy regarding launching a nuclear attack; former British defence secretary Geoff Hoon stated in 2002 and 2003 that the UK would be willing to attack rogue states with them if nuclear weapons were used against British troops. In April 2017 Defence Secretary Michael Fallon confirmed that
31144-561: The communiqué he had signed as obligating the United States to assist Britain in designing, constructing and operating an atomic energy plant. The passing of the Atomic Energy Act of 1946 (McMahon Act) in August 1946, which was signed by Truman on 1 August 1946, and went into effect at midnight on 1 January 1947, ended technical cooperation. Its control of "restricted data" prevented the United States' allies from receiving any information. The remaining British scientists working in
31373-430: The conclusion that there were alternatives to Trident that "would enable the UK to be capable of inflicting significant damage such that most potential adversaries around the world would be deterred", but none would "offer the same degree of resilience as the current posture". The review asserted that whether or not cruise missile-based systems offer a credible alternative was contingent upon a political judgement on whether
31602-408: The detection of aircraft and ships. Radar absorbing material , containing resistive and sometimes magnetic substances, is used on military vehicles to reduce radar reflection . This is the radio equivalent of painting something a dark colour so that it cannot be seen by the eye at night. Radar waves scatter in a variety of ways depending on the size (wavelength) of the radio wave and the shape of
31831-476: The detection process. As an example, moving target indication can interact with Doppler to produce signal cancellation at certain radial velocities, which degrades performance. Sea-based radar systems, semi-active radar homing , active radar homing , weather radar , military aircraft, and radar astronomy rely on the Doppler effect to enhance performance. This produces information about target velocity during
32060-411: The detection process. This also allows small objects to be detected in an environment containing much larger nearby slow moving objects. Doppler shift depends upon whether the radar configuration is active or passive. Active radar transmits a signal that is reflected back to the receiver. Passive radar depends upon the object sending a signal to the receiver. The Doppler frequency shift for active radar
32289-626: The device in patent GB593017. Development of radar greatly expanded on 1 September 1936, when Watson-Watt became superintendent of a new establishment under the British Air Ministry , Bawdsey Research Station located in Bawdsey Manor , near Felixstowe, Suffolk. Work there resulted in the design and installation of aircraft detection and tracking stations called " Chain Home " along the East and South coasts of England in time for
32518-456: The director of the Manhattan Project. He ensured that British participation was complete and wholehearted. Penney worked on means to assess the effects of a nuclear explosion, and wrote a paper on what height the bombs should be detonated at for maximum effect in attacks on Germany and Japan. He served as a member of the target committee established by Groves to select Japanese cities for atomic bombing, and on Tinian with Project Alberta as
32747-423: The distance ( ranging ), direction ( azimuth and elevation angles ), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft , ships , spacecraft , guided missiles , motor vehicles , map weather formations , and terrain . A radar system consists of a transmitter producing electromagnetic waves in the radio or microwaves domain,
32976-493: The early part of the Second World War , the United Kingdom (UK) had a nuclear weapons project, code-named Tube Alloys , which the 1943 Quebec Agreement merged with the American Manhattan Project to create a combined American, British, and Canadian project. The British government expected that the United States (US) would continue to share nuclear technology, which it regarded as a joint discovery, but
33205-538: The electric field is perpendicular to the direction of propagation, and the electric field direction is the polarization of the wave. For a transmitted radar signal, the polarization can be controlled to yield different effects. Radars use horizontal, vertical, linear, and circular polarization to detect different types of reflections. For example, circular polarization is used to minimize the interference caused by rain. Linear polarization returns usually indicate metal surfaces. Random polarization returns usually indicate
33434-421: The end of the Cold War led the British government to conclude that a sub-strategic —but not tactical —role was required. A programme for the replacement of the Vanguard class is under way. On 18 July 2016, the House of Commons voted by a large majority to proceed with building a fleet of Dreadnought -class submarines, to be operational by 2028, with the current fleet completely phased out by 2032. During
33663-473: The entire area in front of it, and then used one of Watson-Watt's own radio direction finders to determine the direction of the returned echoes. This fact meant CH transmitters had to be much more powerful and have better antennas than competing systems but allowed its rapid introduction using existing technologies. A key development was the cavity magnetron in the UK, which allowed the creation of relatively small systems with sub-meter resolution. Britain shared
33892-430: The evolving security environment". The UK has also stated it would no longer declare how many deployable warheads it has in a new policy of deliberate ambiguity. The move is intended to cement the UK's status as a nuclear power and a US defence ally. Labour Party Leader Keir Starmer , although supporting nuclear deterrence, criticised the new policy and questioned why Prime Minister Boris Johnson believed that increasing
34121-574: The final seven missiles previously planned. This saved about £50 million. The UK missiles form a shared pool with the Atlantic squadron of the US Navy Ohio -class SSBNs at Kings Bay. The pool is "co-mingled" and missiles are selected at random for loading on to either nation's submarines. The first Trident boat, HMS Vanguard , collected a full load of 16 missiles in 1994, but Victorious collected only 12 in 1995, and Vigilant , 14 in 1997, leaving
34350-466: The firm GEMA [ de ] in Germany and then another in June 1935 by an Air Ministry team led by Robert Watson-Watt in Great Britain. In 1935, Watson-Watt was asked to judge recent reports of a German radio-based death ray and turned the request over to Wilkins. Wilkins returned a set of calculations demonstrating the system was basically impossible. When Watson-Watt then asked what such
34579-411: The first thermonuclear (hydrogen) bomb . The Soviets responded with Joe 4 , a boosted fission weapon , in 1953. Penney feared that Britain could not afford to develop a hydrogen bomb, as did Tizard, who argued that the nation should focus on conventional forces instead of duplicating the nuclear capabilities of the American forces that were already defending Britain and Europe. He warned that: "We are
34808-538: The first British weapon test would occur before the end of the year. During Operation Hurricane , an atomic bomb was detonated on board the frigate HMS Plym anchored in a lagoon in the Monte Bello Islands in Western Australia on 3 October 1952. Britain thereby became the third country to develop and test nuclear weapons. This led to the development of the first deployed weapon,
35037-499: The flexibility of Trident to provide the vehicle for both sub-strategic and strategic elements of our deterrent … as an insurance against potential adverse trends in the international situation". On 19 March 1998, the Defence Secretary, George Robertson , was asked to provide a statement "on the development of a lower-yield variant of the Trident warhead for the sub-strategic role". He replied, "the UK has some flexibility in
35266-562: The ground-floor main committee room of the Royal Society in Burlington House in London. It directed an intensive research effort, and in July 1941, produced two comprehensive reports that reached the conclusion that an atomic bomb was not only technically feasible, but could be produced before the war ended, perhaps in as little as two years. The Committee unanimously recommended pursuing the development of an atomic bomb as
35495-410: The incident "just weeks before the crucial House of Commons vote on the future of the missile system." Subsequent media reports said this was at the request of the US. Successful Royal Navy test firings had occurred in 2000, 2005, 2009 and 2012. They are infrequent due to the missile's £17 million cost. By August 2016 there had been 161 successful test firings of the Trident II D-5 missile since 1989,
35724-601: The issue in July 1946, and recommended that Britain acquire nuclear weapons. They estimated that 200 bombs would be required by 1957. The Tube Alloys Directorate was transferred from the Department of Scientific and Industrial Research to the Ministry of Supply effective 1 November 1945. To coordinate the atomic energy effort, Marshal of the Royal Air Force Lord Portal , the wartime Chief of
35953-410: The largest British nuclear weapon ever tested. The design of Grapple Y was notably successful because much of its yield came from its thermonuclear reaction instead of fission of a uranium-238 tamper, making it a true hydrogen bomb, and because its yield had been correctly predicted—indicating that its designers understood what they were doing. Eisenhower, now US president, on 22 August 1958 announced
36182-534: The letters is never disclosed, and they are destroyed without being opened upon a new prime minister taking office. By the time of the first Vanguard patrol in December 1994, the Soviet Union no longer existed, and the government adjusted its nuclear policy in the following years. Trident's missiles were "detargetted" in 1994 ahead of Vanguard ' s maiden voyage. The warheads are not aimed at specific targets but await co-ordinates that can be programmed into their computers and fired with several days' notice. Under
36411-559: The mid-1970s. To address this problem, the UK embarked on the development of a Medium Range Ballistic Missile called Blue Streak , but concerns were raised about its own vulnerability, and the British government decided to cancel it and acquire the American Skybolt air-launched ballistic missile . In return, the Americans were given permission to base the US Navy 's Polaris boats at Holy Loch in Scotland. In November 1962,
36640-409: The most recent being from USS Maryland in August 2016. Fewer than 10 test flights have been failures, and the Royal Navy is not known to have had a previous failure. A second failure occurred at the next launch in 2024, although it was reported the fault was specific to the test and would have been unlikely to occur when using a real nuclear warhead. In the 1990s, the total acquisition cost of
36869-513: The obligation to obtain consent for the use of nuclear weapons to merely requiring consultation. The three leaders agreed that there would be full and effective cooperation on atomic energy, but British hopes were soon disappointed; Groves restricted cooperation to basic scientific research. The next meeting of the Combined Policy Committee on 15 April 1946 produced no accord on collaboration, and resulted in an exchange of cables between Truman and Attlee. Truman cabled on 20 April that he did not see
37098-508: The ocean liner Normandie in 1935. During the same period, Soviet military engineer P.K. Oshchepkov , in collaboration with the Leningrad Electrotechnical Institute , produced an experimental apparatus, RAPID, capable of detecting an aircraft within 3 km of a receiver. The Soviets produced their first mass production radars RUS-1 and RUS-2 Redut in 1939 but further development was slowed following
37327-437: The opportunity costs for conventional capabilities that current plans for Trident renewal are due to incur over the next decade...there is now a growing case for a re-examination of whether there are less expensive means of pursuing this objective. A key element of such a review is likely to be a reconsideration of the need to maintain a commitment to CASD in strategic circumstances that are now very different from those in which it
37556-611: The order would be relayed to the Commander, Task Force 345 (CTF 345) operations room at the Northwood Headquarters facility in Hertfordshire , the only facility allowed to communicate with the Vanguard commander on patrol. Communications are relayed via IP over VLF from a transmitter site at Skelton near Penrith. Two personnel are required to authenticate each stage of the process before launching, with
37785-531: The outbreak of World War II in 1939. This system provided the vital advance information that helped the Royal Air Force win the Battle of Britain ; without it, significant numbers of fighter aircraft, which Great Britain did not have available, would always have needed to be in the air to respond quickly. The radar formed part of the " Dowding system " for collecting reports of enemy aircraft and coordinating
38014-1370: The period before and during World War II . A key development was the cavity magnetron in the United Kingdom , which allowed the creation of relatively small systems with sub-meter resolution. The term RADAR was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term radar has since entered English and other languages as an anacronym , a common noun, losing all capitalization . The modern uses of radar are highly diverse, including air and terrestrial traffic control, radar astronomy , air-defense systems , anti-missile systems , marine radars to locate landmarks and other ships, aircraft anti-collision systems, ocean surveillance systems, outer space surveillance and rendezvous systems, meteorological precipitation monitoring, radar remote sensing , altimetry and flight control systems , guided missile target locating systems, self-driving cars , and ground-penetrating radar for geological observations. Modern high tech radar systems use digital signal processing and machine learning and are capable of extracting useful information from very high noise levels. Other systems which are similar to radar make use of other parts of
38243-477: The position that nuclear weapons would give Britain influence over targeting and American policy, and would affect strategy in the Middle East and Far East. His Minister of Defence , Duncan Sandys , considered that nuclear weapons reduced Britain's dependence on the United States. The 1956 Suez Crisis demonstrated that Britain was no longer a great power, but increased the value to Britain of an independent nuclear deterrent that would give it greater influence with
38472-407: The post-war period. A British mission led by Akers assisted in the development of gaseous diffusion technology at the SAM Laboratories in New York. Another, led by Oliphant, who acted as deputy director at the Berkeley Radiation Laboratory , assisted with the electromagnetic separation process. Cockcroft became the director of the Anglo-Canadian Montreal Laboratory . The British mission to
38701-706: The primary tool for short-term weather forecasting and watching for severe weather such as thunderstorms , tornadoes , winter storms , precipitation types, etc. Geologists use specialized ground-penetrating radars to map the composition of Earth's crust . Police forces use radar guns to monitor vehicle speeds on the roads. Automotive radars are used for adaptive cruise control and emergency breaking on vehicles by ignoring stationary roadside objects that could cause incorrect brake application and instead measuring moving objects to prevent collision with other vehicles. As part of Intelligent Transport Systems , fixed-position stopped vehicle detection (SVD) radars are mounted on
38930-407: The programme by 409 votes to 161. Faslane Peace Camp is permanently sited near Faslane naval base. It has been occupied continuously, albeit in different locations, since 12 June 1982. In 2006, a year-long protest at Trident's base at Faslane aimed to blockade the base every day for a year. More than 1,100 people were arrested. During the 2020 coronavirus pandemic a letter was circulated to MPs by
39159-400: The project, with the Devonshire Dock Hall built specially for it. The initial plan was to build new versions of the Resolution -class, but in July 1981 the decision was taken to incorporate the new Rolls-Royce PWR2 pressurised water reactor . From the outset, the Vanguard submarines were designed with enlarged missile tubes able to accommodate the Trident II D-5. The missile compartment
39388-432: The radial component of the velocity is relevant. When the reflector is moving at right angle to the radar beam, it has no relative velocity. Objects moving parallel to the radar beam produce the maximum Doppler frequency shift. When the transmit frequency ( F T {\displaystyle F_{T}} ) is pulsed, using a pulse repeat frequency of F R {\displaystyle F_{R}} ,
39617-417: The relationship with Britain that had been damaged by the Suez Crisis. Macmillan wrote to Eisenhower on 10 October urging that the two countries pool their resources to meet the challenge. British information security, or the lack thereof, no longer seemed so important now that the Soviet Union was apparently ahead, and British scientists had demonstrated that they understood how to build a hydrogen bomb with
39846-401: The remaining missile tubes empty. By 1999, six missiles had been test fired, and another eight were earmarked for test firing. In June 2016, a Trident II D-5 missile "veered off in the wrong direction towards America" after being launched from Vengeance off the coast of Florida. The incident was not revealed until January 2017; the Sunday Times reported that Downing Street had "covered up"
40075-401: The replacement of Polaris with Trident would involve an escalation in the numbers of British nuclear weapons. When the decision to purchase Trident II was announced in 1982, it was stressed that while American Trident boats carried 24 missiles with eight warheads each, a total of 192 warheads, British Trident boats would carry no more than 128 warheads—the same number as Polaris. In November 1993,
40304-414: The response. Given all required funding and development support, the team produced working radar systems in 1935 and began deployment. By 1936, the first five Chain Home (CH) systems were operational and by 1940 stretched across the entire UK including Northern Ireland. Even by standards of the era, CH was crude; instead of broadcasting and receiving from an aimed antenna, CH broadcast a signal floodlighting
40533-410: The resulting frequency spectrum will contain harmonic frequencies above and below F T {\displaystyle F_{T}} with a distance of F R {\displaystyle F_{R}} . As a result, the Doppler measurement is only non-ambiguous if the Doppler frequency shift is less than half of F R {\displaystyle F_{R}} , called
40762-407: The retirement of the Nimrod maritime patrol aircraft in 2011 gave Russia the potential to gain "valuable intelligence" on the country's nuclear deterrent. As a result, plans to buy Northrop Grumman MQ-4C Triton unmanned aerial vehicles were reportedly considered. The Strategic Defence and Security Review 2015 announced that nine Boeing P-8 Poseidon maritime patrol aircraft would be purchased for
40991-427: The roadside to detect stranded vehicles, obstructions and debris by inverting the automotive radar approach and ignoring moving objects. Smaller radar systems are used to detect human movement . Examples are breathing pattern detection for sleep monitoring and hand and finger gesture detection for computer interaction. Automatic door opening, light activation and intruder sensing are also common. A radar system has
41220-460: The same arming, fusing and firing system (AF&F) as the US W76-1. This new AF&F system, called the MC4700, would increase weapon lethality against hard targets such as missile silos and bunkers. Due to the distance of 720 km (450 mi) between AWE Aldermaston and the UK's nuclear weapon storage depot at RNAD Coulport, Holbrook (Trident) warheads are transported by road in heavily armed convoys by Ministry of Defence Police . According to
41449-407: The scattered energy back toward the source. The extent to which an object reflects or scatters radio waves is called its radar cross-section . The power P r returning to the receiving antenna is given by the equation: where In the common case where the transmitter and the receiver are at the same location, R t = R r and the term R t ² R r ² can be replaced by R , where R
41678-412: The steel bung was removed and the ball bearings spilled on the floor of an aircraft hangar, leaving the bomb armed and dangerous. About ten were delivered. The scientists at Aldermaston had not yet mastered the design of thermonuclear weapons. They produced a new design, called Round A. Another trial was scheduled, known as Grapple X. Round A was dropped on 8 November 1957. To save time and money,
41907-471: The stockpile was necessary. Kate Hudson of the Campaign for Nuclear Disarmament warned against the start of a "new nuclear arms race". Four Vanguard -class submarines were designed and built at Barrow-in-Furness by Vickers Shipbuilding and Engineering, now BAE Systems Submarines , the only shipbuilder in the UK with the facilities and expertise to build nuclear submarines. Even so, £62 million worth of new shipbuilding and dock facilities were added for
42136-524: The submarine commander only able to activate the firing trigger after two safes have been opened with keys held by the ship's executive and weapon engineer officers. A parliamentary answer states that commanding officers of Royal Navy ballistic submarines receive training in the 'Law Of Armed Conflict'. Trident is based at HMNB Clyde on the west coast of Scotland. The base consists of two facilities — Faslane Naval Base on Gare Loch near Helensburgh , and an ordnance depot with 16 concrete bunkers set into
42365-475: The surface behind the submarine to pick up incoming messages. Most of the 150 crew never know where they are or where they have been. The 350th patrol commenced on 29 September 2017. On 15 November 2018, a reception was held at Westminster to mark 50 years of CASD. Only the prime minister or a designated survivor can authorise the missiles to be fired. These orders would likely be issued from the Pindar command bunker under Whitehall in central London. From there,
42594-487: The target was off the southern tip of Christmas Island rather than off Malden Island, just 20 nautical miles (37 km; 23 mi) from the airfield where 3,000 men were based. This time the yield of 1.8 megatonnes of TNT (7.5 PJ) exceeded expectations. Round A was a true hydrogen bomb, but it used a relatively large quantity of expensive highly enriched uranium. Aldermaston had plenty of ideas about how to follow up Grapple X. A new design used lithium deuteride that
42823-491: The target. If the wavelength is much shorter than the target's size, the wave will bounce off in a way similar to the way light is reflected by a mirror . If the wavelength is much longer than the size of the target, the target may not be visible because of poor reflection. Low-frequency radar technology is dependent on resonances for detection, but not identification, of targets. This is described by Rayleigh scattering , an effect that creates Earth's blue sky and red sunsets. When
43052-415: The technology with the U.S. during the 1940 Tizard Mission . In April 1940, Popular Science showed an example of a radar unit using the Watson-Watt patent in an article on air defence. Also, in late 1941 Popular Mechanics had an article in which a U.S. scientist speculated about the British early warning system on the English east coast and came close to what it was and how it worked. Watson-Watt
43281-436: The terms of the 1987 Intermediate-Range Nuclear Forces Treaty with the Soviet Union, the US withdrew its surface naval nuclear weapons and short-range nuclear forces. The GLCMs were withdrawn from the UK in 1991, and the Polaris submarine base at Holy Loch was closed in 1992. The last US warheads in British service under Project E , the B57 nuclear depth bombs and the Lance missiles and W48 nuclear artillery shells used by
43510-408: The terms of the Polaris Sales Arrangement, the US does not have a veto on the use of British nuclear weapons, which the UK may launch independently, but this would only occur if "supreme national interests" required it. The final decision on firing the missiles is the responsibility of the prime minister, who, upon taking office, writes four identical letters of last resort , one of which is locked in
43739-879: The transmitter. The reflected radar signals captured by the receiving antenna are usually very weak. They can be strengthened by electronic amplifiers . More sophisticated methods of signal processing are also used in order to recover useful radar signals. The weak absorption of radio waves by the medium through which they pass is what enables radar sets to detect objects at relatively long ranges—ranges at which other electromagnetic wavelengths, such as visible light , infrared light , and ultraviolet light , are too strongly attenuated. Weather phenomena, such as fog, clouds, rain, falling snow, and sleet, that block visible light are usually transparent to radio waves. Certain radio frequencies that are absorbed or scattered by water vapour, raindrops, or atmospheric gases (especially oxygen) are avoided when designing radars, except when their detection
43968-456: The treaty for another five or ten years; others added definitions and made minor changes. As of 2018 , the most recent renewal was on 22 July 2014, extending the treaty to 31 December 2024. A 1974 US proliferation report discussing British nuclear and missile development noted that "In many cases, it is based on technology received from the US and could not legitimately be passed on without US permission." Production of British nuclear weapons
44197-487: The two length scales are comparable, there may be resonances . Early radars used very long wavelengths that were larger than the targets and thus received a vague signal, whereas many modern systems use shorter wavelengths (a few centimetres or less) that can image objects as small as a loaf of bread. Short radio waves reflect from curves and corners in a way similar to glint from a rounded piece of glass. The most reflective targets for short wavelengths have 90° angles between
44426-559: The uranium nucleus had been split, a conclusion they published in Nature in 1939. By analogy with the division of biological cells , they named the process " fission ". The discovery of fission raised the possibility that an extremely powerful atomic bomb could be created. The term was already familiar to the British public through the writings of H. G. Wells , with a continuously exploding bomb in his 1913 novel The World Set Free . George Paget Thomson , at Imperial College London , and Mark Oliphant , an Australian physicist at
44655-418: The use of radar altimeters possible in certain cases. The radar signals that are reflected back towards the radar receiver are the desirable ones that make radar detection work. If the object is moving either toward or away from the transmitter, there will be a slight change in the frequency of the radio waves due to the Doppler effect . Radar receivers are usually, but not always, in the same location as
44884-458: The world's first artificial satellite , on 4 October 1957, came as a tremendous shock to the American public, who had trusted that American technological superiority ensured their invulnerability. Now, suddenly, there was incontrovertible proof that, in some areas at least, the Soviet Union was actually ahead. In the widespread calls for action in response to the Sputnik crisis , officials in the United States and Britain seized an opportunity to mend
45113-400: Was launched in 1960 and commissioned in 1963. The S5W had a nuclear reactor core that used uranium enriched to between 93 and 97 per cent uranium-235. Reactor technology was transferred from Westinghouse to Rolls-Royce , which used it as the basis for its PWR1 reactor used in the UK's nuclear submarines. The MDA has been renewed or amended many times. Most amendments merely extended
45342-456: Was merged with the American Manhattan Project . The British government considered nuclear weapons to be a joint discovery, but the American Atomic Energy Act of 1946 (McMahon Act) restricted other countries, including the UK, from access to information about nuclear weapons. Fearing the loss of Britain's great power status, the UK resumed its own project, now codenamed High Explosive Research . On 3 October 1952, it detonated an atomic bomb in
45571-608: Was a 1938 Bell Lab unit on some United Air Lines aircraft. Aircraft can land in fog at airports equipped with radar-assisted ground-controlled approach systems in which the plane's position is observed on precision approach radar screens by operators who thereby give radio landing instructions to the pilot, maintaining the aircraft on a defined approach path to the runway. Military fighter aircraft are usually fitted with air-to-air targeting radars, to detect and target enemy aircraft. In addition, larger specialized military aircraft carry powerful airborne radars to observe air traffic over
45800-473: Was anticipated that there would be sufficient British megaton weapons to equip the entire strategic bomber force. Project E weapons were replaced by British Yellow Sun bombs. Problems encountered in the development of Red Beard meant that the replacement of kiloton weapons took longer than anticipated. The Air Ministry decided to replace the Canberras with Valiants as the long-range Vulcan and Victor V bombers became available. A Valiant squadron at RAF Marham
46029-404: Was assigned to SACEUR on 1 January 1961, followed by two more in July. The UK-based Canberra squadrons were then disbanded. Each of the 24 Valiants was equipped with two Project E Mark 28 nuclear bombs . These were replaced by the newer Mark 43 nuclear bombs in early 1963. The Valiants were withdrawn from service in 1965. Radar Radar is a system that uses radio waves to determine
46258-456: Was attempted by USS Tennessee in March 1989. This attempt failed because the plume of water following the missile rose to a greater height than expected, resulting in water being in the nozzle when the motor ignited. Once the problem was understood, simple changes were quickly made, but the problem delayed the entry into service of Trident II until March 1990. Trident II D-5 is more sophisticated than its predecessor, Trident I C-4, and has
46487-431: Was being lifted from 180 to 260. The warheads are primarily constructed at AWE Aldermaston , with other parts being made at other AWE facilities such as Burghfield . The British government insists the warhead is indigenously designed, but analysts including Hans M. Kristensen with the Federation of American Scientists believe that it is largely based on the US W76 design. Under the 1958 US–UK Mutual Defence Agreement
46716-574: Was completed on 4 December 1969. The four Resolution -class boats were based at HMNB Clyde at Faslane on the Firth of Clyde , not far from the US Navy's base at Holy Loch, which opened in August 1968. It was served by a weapons store at nearby RNAD Coulport . HM Dockyard, Rosyth , was designated as the refit yard for the 10th Submarine Squadron , as the Polaris boats became operational. Polaris proved to be reliable, and its second-strike capability conferred greater strategic flexibility than any previous British nuclear weapons system. However it had
46945-509: Was designed as a strategic deterrent, the end of the Cold War led the British government to conclude that a sub-strategic —but not tactical —role was required, with Trident missiles assuming the role formerly handled by the RAF's WE.177 bombs. The 1994 Defence White Paper stated: "We also need the capability to undertake nuclear action on a more limited scale in order to ... halt aggression without inevitably triggering strategic nuclear exchanges". A later statement read: "We also intend to exploit
47174-577: Was developed in collaboration with Microsoft , and is based on the same technology as Windows XP , which led the media to give it the nickname "Windows for Submarines", with the UK Defence Journal fact checking group countering claims the vessels run on Windows XP . In addition to the missile tubes, the submarines are fitted with four 21-inch (533 mm) torpedo tubes and carry the Spearfish torpedo , allowing them to engage submerged or surface targets at ranges up to 65 kilometres (40 mi; 35 nmi). Two SSE Mark 10 launchers are also fitted, allowing
47403-460: Was elected president. Part of his election platform was to modernise the US strategic nuclear forces. On 24 August 1981, the Reagan administration informed the British government of its intention to upgrade its Trident to the new Trident II D-5 missile by 1989, and indicated that it was willing to sell it to the UK. Despite the name, the D-5 was not an improved version of the C-4, but a completely new missile. Its purchase had already been considered in
47632-430: Was embarrassing to the British (who had not expected a Soviet atomic weapon until 1954) for having been beaten, it was for the Americans another reason for cooperation. Although they would soon have their own nuclear capability, the British proposed that instead of building their own uranium-enrichment plant they would send most of their scientists to work in the US, and swap plutonium from Windscale for enriched uranium from
47861-426: Was estimated at 300 kilotonnes of TNT (1,300 TJ), far below its designed capability. Despite its failure, the test was hailed as a successful thermonuclear explosion, and the government did not confirm or deny reports that the UK had become a third thermonuclear power. When documents on the series began to be declassified in the 1990s, the Grapple X tests were denounced as a hoax. The reports would not have fooled
48090-436: Was first introduced." The 2013 Trident Alternatives Review was an 18-month study led by the Cabinet Office that was aimed at establishing whether or not there were credible alternatives to the UK's submarine-based CASD. Accordingly, the review analysed a range of delivery systems and warhead designs with respect to their affordability and effectiveness against potential targets. Ultimately, the Trident Alternatives Review came to
48319-484: Was followed by her sisters, HMS Victorious , which was laid down on 3 December 1987 and commissioned on 7 January 1995; HMS Vigilant , which was laid down on 16 February 1991 and commissioned on 2 November 1996; and HMS Vengeance , which was laid down on 1 February 1993 and commissioned on 27 November 1999. The first British Trident missile was test-fired from Vanguard on 26 May 1994, and she began her first patrol in December of that year. According to
48548-638: Was given little chance of winning the 1983 election in the aftermath of the Falklands War, polls had shown Labour ahead of the Conservatives in 1986 and 1987. In the wake of Labour's unsuccessful performance in the 1987 election , the Labour Party leader, Neil Kinnock , despite his own unilateralist convictions, moved to drop the party's disarmament policy, which he saw as a contributing factor in its defeat. The party formally voted to do so in October 1989. Pro-independence Scottish political parties—the Scottish National Party (SNP), Scottish Green Party , Scottish Socialist Party (SSP) and Solidarity —are opposed to
48777-592: Was high explosive. The first Blue Danube bombs were delivered to the Royal Air Force (RAF) Bomber Command in November 1953, although the bombers to deliver them did not become available until 1955. On 11 October 1956, a Vickers Valiant from No. 49 Squadron RAF piloted by Edwin Flavell became the first British aircraft to drop a live atomic bomb when a Blue Danube was exploded over Maralinga, South Australia during Operation Buffalo . About fifty-eight Blue Danube bombs were produced. The first bombs had plutonium cores , but all service models were modified to use
49006-403: Was launched on 15 September 1965, commissioned on 2 October 1967, and conducted a test firing at the American Eastern Range on 15 February 1968. She was followed by HMS Repulse , which was completed by Vickers-Armstrongs on 29 September 1968; and two boats built by Cammell Laird in Birkenhead : HMS Renown , which was completed on 15 November 1968; and HMS Revenge , which
49235-502: Was less enriched in lithium-6 (and therefore had more lithium-7 ), but more of it, thereby reducing the amount of uranium-235 in the core. Because of the possibility of an international moratorium on atmospheric testing, plans for the trial, codenamed Grapple Y, were given verbal approval by the Prime Minister, and known only to a handful of officials. The bomb was dropped off Christmas Island on 28 April 1958. It had an explosive yield of about 3 megatonnes of TNT (13 PJ), and remains
49464-439: Was necessary to avert trouble over the Belizean–Guatemalan territorial dispute . They accepted a counter-offer that Britain would retain the two landing platform dock ships, HMS Fearless and Intrepid , for which the Americans reduced the R&D charge. Under the agreement, the UK would purchase 65 Trident II D-5 missiles that would operate as part of a shared pool of weapons based at Naval Submarine Base Kings Bay in
49693-440: Was needed to overcome the Soviet ABM defences. Callaghan approached President Jimmy Carter in January 1979, who responded positively, but did not commit. The Carter administration's main priority was the SALT II Agreement with the Soviet Union, which limited nuclear weapons stockpiles. It was signed on 18 June 1979, but Carter faced an uphill battle to secure its ratification by the US Senate . MIRV technology had proved to be
49922-411: Was not the case. Instead of the 5 per cent levy in recognition of US research and development (R&D) costs agreed to in the Polaris Sales Agreement, a 1976 law now required a pro rata fixed fee payment; the levy would have been approximately $ 100 million, however the fixed fee amounted to around $ 400 million. The law could be waived if the President determined that it was in the interest of
50151-413: Was now the Prime Minister, during their March 1957 meeting in Bermuda, and a formal Memorandum of Understanding (MOU) was signed on 21 May 1957. Four squadrons of English Electric Canberra bombers based in Germany were equipped with US Mark 7 nuclear bombs stored at RAF Germany bases. There were also four squadrons of nuclear-armed Canberras based in the UK, which were capable of carrying either
50380-486: Was ordered on 30 April 1986. In view of the Labour Party's continued opposition to Trident, Vickers insisted that the contract include substantial compensation in the event of cancellation. The Trident programme was initiated during the Cold War , and it was designed to provide an ongoing independently controlled deterrent against major threats to the security of the UK and its NATO allies, including threats posed by non-nuclear weapons. To provide an effective deterrent,
50609-403: Was publicly announced in the House of Commons on 12 May 1948. D notice No. 25 prohibited the publication of details on the design, construction or location of atomic weapons. The project was given the cover name "High Explosive Research". As Chief Superintendent Armament Research (CSAR, pronounced "Caesar"), Penney directed bomb design from Fort Halstead . In 1951, his design group moved to
50838-422: Was replaced by Red Beard , a smaller tactical nuclear weapon. The Blue Danube cores were recycled, and the plutonium used in other nuclear weapons. Being so big and heavy, Blue Danube could only be carried by the V bombers , so-called because they all had names starting with a "V". The three strategic bombers, known collectively as the V class, comprised the United Kingdom's strategic nuclear strike force during
51067-413: Was seen as an important player in world affairs, its economic and military weaknesses offset by its membership of NATO and the Group of Seven , its then active membership of the European Union , its permanent seat on the UN Security Council , its leadership of the Commonwealth of Nations , and the nuclear Special Relationship with the US. To accept a position of inferiority to its ancient rival, France,
51296-748: Was sent to the U.S. in 1941 to advise on air defense after Japan's attack on Pearl Harbor . Alfred Lee Loomis organized the secret MIT Radiation Laboratory at Massachusetts Institute of Technology , Cambridge, Massachusetts which developed microwave radar technology in the years 1941–45. Later, in 1943, Page greatly improved radar with the monopulse technique that was used for many years in most radar applications. The war precipitated research to find better resolution, more portability, and more features for radar, including small, lightweight sets to equip night fighters ( aircraft interception radar ) and maritime patrol aircraft ( air-to-surface-vessel radar ), and complementary navigation systems like Oboe used by
51525-409: Was slow and Britain had only ten atomic bombs on hand in 1955 and just fourteen in 1956. At the three-power Bermuda Conference with Eisenhower in December 1953, Churchill suggested that the United States allow Britain to have access to American nuclear weapons to make up the shortfall. The provision on American weapons was called Project E . The agreement was confirmed by Eisenhower and Macmillan, who
51754-448: Was stockpiled at Springfields. As the American nuclear programme expanded, its requirements became greater than the production of the existing mines. To gain access to the stockpile, they reopened negotiations in 1947. This resulted in the 1948 Modus Vivendi , which allowed for consultation on the use of nuclear weapons, and limited sharing of technical information between the United States, Britain and Canada. The United States feared
51983-434: Was succeeded by Margaret Thatcher after the general election on 3 May 1979, and she discussed the issue with Carter in October, who agreed to supply C-4, but he asked that the UK delay a formal request until December in order that he could get SALT II ratified beforehand. In the meantime, the MDA, without which the UK would not be able to access US nuclear weapons technology, was renewed for five more years on 5 December, and
52212-411: Was the first to use radio waves to detect "the presence of distant metallic objects". In 1904, he demonstrated the feasibility of detecting a ship in dense fog, but not its distance from the transmitter. He obtained a patent for his detection device in April 1904 and later a patent for a related amendment for estimating the distance to the ship. He also obtained a British patent on 23 September 1904 for
52441-513: Was unthinkable. Moreover, the UK sees itself as a force for good in the world with a moral duty to intervene, with military force if need be, to defend both its interests and its values. By the 1980s, possession of nuclear weapons was considered a visible sign of Britain's enduring status as a great power in spite of the loss of the British Empire , and had become a component of the national self-image. The Cabinet Secretary , Sir John Hunt briefed Cabinet on Polaris on 28 November 1977, noting that
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