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Weapons of Mass Destruction (WMD)

The Future of Britain's WMD


A history of American support for Britain's Weapons of Mass Destruction

British dependence on the US for nuclear weapons started in the Second World War. This history shows that it is incorrect to think that the UK was ever an independent nuclear state like France , Russia or China .

In 1940, Churchill initiated work on a British atomic bomb, rejecting a suggestion of cooperation from the US President, Franklin Roosevelt in October 1941.24 He soon realised that Britain did not have the resources to go it alone and sought to get involved with the US , but it was not until the 1943 Quebec Agreement that Britain joined the Manhattan project that built the Hiroshima and Nagasaki bombs.

Margaret Gowing, the official historian of Britain ’s nuclear weapons explains that: ‘ Britain had then become only a junior partner in the business, contributing significantly in various ways but present largely on American sufferance’.25 In 1946, the US Congress passed the MacMahan Act to stop nuclear collaboration with any state. British scientists returned home with information on how to build an atom bomb but without detailed knowledge of the industrial production processes.

Some nuclear sharing quickly restarted, as the US needed supplies of British controlled uranium ore from the Congo , despite the MacMahan Act.26 Until 1952, the US intermittently provided the UK with nine categories of information mostly on the construction of nuclear reactors for making nuclear explosives.27 Congressional leaders brought into the negotiations threatened to withdraw the Marshal Aid programme to get the Attlee government to give up joint control over the use of nuclear weapons agreed by Churchill and Roosevelt during the war.28

In 1947, the British atomic bomb project was restarted by the Labour government. In Peter Hennessy’s account, it was the Foreign Secretary Ernest Bevin’s intervention that swung the discussion amongst ministers.29 And the need to have a ‘Union Jack’ on top of the bomb, in Bevin’s famous phrase, was driven by the humiliating way that Bevin had just been spoken to by the US Secretary of State James Byrnes. The programme was mentioned in Parliament in 1948, with more detail only provided shortly before the first British atomic test in 1952 under Winston Churchill’s premiership.30 Churchill privately expressed surprise at how much money and work had been done in secret by the Labour government.

From 1948, the US began to base nuclear capable bombers in Britain . One of Churchill’s last political acts was to try to reach out to the Soviet leadership after the death of Stalin in order to control the hydrogen bomb. He found he had no influence in Washington and, shortly before retiring, Churchill began the UK hydrogen bomb programme, while privately expressing greater concern over the future of the world than he had even in 1940.

Despite the great effort to produce the atomic bomb and jet bombers to carry them, the development of hydrogen bombs and ballistic missiles to carry them by both the US and Russia in the 1950s made it impossible for the UK to afford an independent nuclear weapons system.

In 1957, with great difficulty and expense, the UK exploded its first hydrogen bomb and, shortly thereafter, the US agreed to provide full support for the British nuclear weapons programme . As both Lorna Arnold and Peter Hennessy describe in their studies of the British hydrogen bomb programme , the key purpose in the mind of the Prime Minister, Harold Macmillan, was to show the Americans that the British were important enough a nuclear power to help, rather than to have an independent weapon.

In 1958, the US-UK Mutual Defence Agreement (MDA) was signed, although very little was known about it in public. It has been renewed periodically ever since, the last time in 2004. The MDA allows the US to provide the UK with nuclear weapons designs, nuclear weapons manufacturing and nuclear reactor technology, designs and materials.

A secret British government assessment of ‘The Dangers of Becoming an American Satellite’, only released after 1988, stated:

The UK , in its relatively weak position, is already greatly dependent upon United States support. It would be surprising if the United States did not exact a price for the support, and to some extent it does so…the more we rely upon them, the more we shall be hurt if they withhold it.31

Nuclear explosive materials

Tons of uranium and plutonium were traded between the UK and he US during the Cold War. This was flatly denied at the time. In 1997, the Clinton Administration revealed the extent of this exchange (details in the Appendix). Ross Hesketh wrote that the 5.4 tonnes of plutonium sent to the USA amounted to ‘the entire production of plutonium from all the UK civil nuclear power stations, up to April 1969, according to official sources’.32 This trade was helpful to the Americans, but vital to the British nuclear weapons programme.

Today, renewed British interest in nuclear energy should be examined closely for any commercial, political or technical connection to nuclear weapons. How, for example, can the British government be serious about being a nuclear weapons power if it is not going to have a modern nuclear industry?

Nuclear warhead design and construction

The 1958 MDA created the Joint Atomic Information Exchange Group and dozens of Joint Working Groups (JOWOGs). Documents obtained by the US Natural Resources Defense Council show that the US supplied the designs of many weapons to the British. The UK national archives on the JOWOGs, even from 1960, are still sealed. The titles of some documents from that era show that the UK was briefed on the use of beryllium, plutonium and uranium and the Americans were presented with the results of British experiments using US supplied bomb parts. US officials also benefit from the exchanges because of the innovative and skilful approach of their resource-starved British counterparts.

In the early 1960s, public concern over the nuclear arms race focused on the test explosions of nuclear weapons in the atmosphere and the accumulation of radiation in milk. After the 1963 UK/US/USSR agreement of the atmospheric test ban, the UK was only able to carry out test explosions jointly with the US at the underground test site in Nevada . Then, President Clinton’s support for a test ban forced John Major’s government to follow suit and sign the Comprehensive Test Ban Treaty in 1996. The last US/UK tests at Nevada were codenamed Barnwell (1989), Houston (1990) and Bristol (1991).

For many years, the JOWOGs were secret and were only obliquely referred to in the open literature. Thus, two of the main British academic studies on Anglo-American defence relations and nuclear weapons make no more than a passing reference to them.33 It was only through the work of the Natural Resources Defence Council in Washington , D.C. , Greenpeace UK and BASIC, that the JOWOGs were first discussed in public. Subsequent activity by MPs such as Frank Cook and Alan Simpson led to the British government providing occasional lists of the JOWOGs to Parliament.34

The principal role of the JOWOGs is to assist the British in producing nuclear warheads. Since the mid-1960s, the UK has deployed four types of nuclear weapon, some with variants. These are the WE-177, Polaris, Chevaline/Polaris and Trident. Only Trident is in service today.

The RAF and Royal Navy used the WE-177 free-fall bomb with three versions for different military tasks. However, the British only conducted three nuclear tests in the period when the weapon was developed, making a British-only design most unlikely. Quite how the warhead was designed remains a secret. However, an analysis by the Natural Resources Defense Council (NRDC) concludes that the WE177 was probably based on US designs (Mark 57 and B61). A declassified US document from 1960 obtained by the NRDC says that the UK : ‘plans to produce several versions of the Mark 57.’35

The US supplied the design for Polaris (the W-58). In heated exchanges in the House of Commons between the Prime Minister Lord Home and Harold Wilson, Home confusingly said that the Polaris warhead was probably ‘both’ the US design and a British design of the same size.36 Further evidence that the Polaris warhead was not a British design was that Home saw no need to test it at all, although Harold Wilson did get US permission to conduct one.

In the early 1970s, the US stopped the key part of the JOWOG cooperation when the Labour government said that would not have a new nuclear weapon. There was consternation at Aldermaston at the loss of access to US bomb-makers. US support resumed when, under the premierships of Edward Heath and Harold Wilson, a secret programme to put a new warhead on Polaris was begun. This programme, known as Chevaline or ‘Super-Antelope’ in Britain , was based on Lockheed’s US Antelope project. Technically, its function was to defeat Soviet missile defences, but politically its function was to keep US nuclear support.37

In 1979, Margaret Thatcher’s new Defence Secretary, Francis Pym, announced Chevaline in Parliament. This caused much infighting in the Labour Party, whose members had known nothing of this programme, which was in violation of the decisions of the party conference.38


Forty years ago, Harold Macmillan had to deal with the fact that not only could the government not afford independent bombs, it could not afford independent missiles either. His government first sought a US air-launched missile, Skybolt, and, when this was cancelled, was offered the US Navy’s Polaris missile.

The December 1962 Nassau agreement to provide the UK with Polaris provided the UK with missiles, submarine and reactor technology. President Kennedy offered a similar deal to the French President Charles de Gaulle.39 In January 1963, De Gaulle made a speech rejecting the US offer of Polaris to France and vetoing British membership of the Common Market on the grounds that the British had now come under US control.

Macmillan’s Permanent Secretary, Sir Robert Scott, recorded that the decision has ‘put us in America ’s pocket for a decade.’40 The commander of the Royal Air Force nuclear bomber force wrote privately that the deal had been done to sustain the ‘myth’ of an independent force.41

The two key agreements on US support made by Macmillan (the MDA and Polaris) were made because Britain was too weak to act independently. This underlying fact has meant that no government has sought to change the framework of agreements established by Macmillan, rather, they have been anxious to ensure that the US keeps renewing them.

The Labour government of Harold Wilson came to power in 1964. Its manifesto said that Polaris: ‘will not be independent and it will not be British and it will not deter.’ Nevertheless, with most of the money committed, the Wilson Cabinet, with the support of Parliament, continued the programme, although even in retirement he said: ‘I never believed that we had a really independent deterrent.’42

Air Vice Marshal Stuart Menaul wrote in 1980 that:

Britain no longer has an independent nuclear deterrent…strategic considerations as far as Britain is concerned are no longer relevant…it could only be used after authority for the use of nuclear weapons had been conveyed from the President of the United States to SACEUR [the US general at NATO].43

24 ‘British Thinking about Nuclear Weapons’, A.J.R. Groom, Pinter, 1974, Chapter 1

25 ‘ Independence and Deterrence’, Margaret Gowing, Macmillan, 1974, Vol 1 p.3

26 ‘Nuclear Rivals: Anglo-American Atomic relations 1941-1952’, S. Paul, Ohio University Press, 2000, passim.

27 Ibid.

28 Groom, op. cit., p.31.

29 Hennessy, op. cit.

30 Gowing, op. cit.

31 ‘Planning Paper on Interdependence’, Foreign Office, SC (58)8, Steering Committee, 27 January 1958, PRO FO371/132330, quoted in J. Baylis, ‘Anglo-American defence relations 1939-1984’, 2 nd edition, Macmillan, London 1984.

32,,60-1091224,00.html 29 April 2004 , accessed 1 July 2005 .

33 ‘The Independent Nuclear State’, J. Simpson, MacMillan, London , 1986 and ‘Anglo American Relations since 1939’, J. Baylis, Manchester University Press, 1997.

34 Alan Simpson MP, House of Commons, Hansard, 15 December 1994 , c 1222.

35 ‘Safety of British Nuclear Weapon Designs’, W. Peden , British American Security Information Council, 1991.

36 House of Commons, Hansard, 12 May 1964 , c222-223

37 ‘Aldermaston and British Nuclear Weapons Development: Testing the “Zuckerman Thesis”’, G. Spinardi, Social Studies of Science, Vol 27, 1997, pp547-582.

38 House of Commons, Hansard, 15 February 1989 , c 383.


40 Cited in I. Clark , op. cit., p 413.

41 Cited in I. Clark , op. cit., p 418.

42 Hennessy, op. cit., p70 ff.

43 ‘Countdown’, S. Menaul , Hale, London , 1980, p 7 and 172.

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