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Polaris Sales Agreement

Treaty between the United States and the United Kingdom

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The United Kingdom had been planning to buy the air-launched Skybolt missile to extend the operational life of the British V bombers, but the United States decided to cancel the Skybolt program in 1962 as it no longer needed the missile. The crisis created by the cancellation prompted an emergency meeting between the president of the United States, John F. Kennedy, and the prime minister of the United Kingdom, Harold Macmillan, which resulted in the Nassau Agreement, under which the United States agreed to provide Polaris missiles to the United Kingdom instead.

The Polaris Sales Agreement provided for the implementation of the Nassau Agreement. The United States would supply the United Kingdom with Polaris missiles, launch tubes, and the fire control system. The United Kingdom would manufacture the warheads and submarines. In return, the US was given certain assurances by the United Kingdom regarding the use of the missile, but not a veto on the use of British nuclear weapons. The British Resolution-class Polaris ballistic missile submarines were built on time and under budget, and came to be seen as a credible deterrent.

Along with the 1958 US–UK Mutual Defence Agreement, the Polaris Sales Agreement became a pillar of the nuclear Special Relationship between Britain and the United States. The agreement was amended in 1982 to provide for the sale of the Trident missile system.

Background

During the early part of the Second World War, Britain had a nuclear weapons project, codenamed Tube Alloys. In August 1943, the prime minister of the United Kingdom, Winston Churchill and the president of the United States, Franklin Roosevelt, signed the Quebec Agreement, which merged Tube Alloys with the American Manhattan Project. The British government trusted that the United States would continue to share nuclear technology, which it regarded as a joint discovery, but the 1946 McMahon Act ended cooperation. Fearing a resurgence of United States isolationism, and Britain losing its great power status, the British government restarted its own development effort, now codenamed High Explosive Research. The first British atomic bomb was tested in Operation Hurricane on 3 October 1952. The subsequent British development of the hydrogen bomb, and a favourable international relations climate created by the Sputnik crisis, led to the McMahon Act being amended in 1958, and the restoration of the nuclear Special Relationship in the form of the 1958 US–UK Mutual Defence Agreement (MDA), which allowed Britain to acquire nuclear weapons systems from the United States.

Britain's nuclear weapons armament was initially based on free-fall bombs delivered by the V bombers of the Royal Air Force (RAF), but the possibility of the crewed bomber becoming obsolete by the late 1960s due to improvements in anti-aircraft defences was foreseen. In 1953, work began on a medium-range ballistic missile (MRBM) called Blue Streak, but by 1958, there were concerns about the vulnerability of this liquid-propellant-missile to a pre-emptive nuclear strike. To extend the effectiveness and operational life of the V bombers, an air-launched, rocket-propelled standoff missile called Blue Steel was developed, but it was anticipated that the air defences of the Soviet Union would improve to the extent that V bombers might still find it difficult to attack their targets. A solution appeared to be the American Skybolt missile, which combined the range of Blue Streak with the mobile basing of the Blue Steel, and was small enough that two could be carried on an Avro Vulcan bomber.

An institutional challenge to Skybolt came from the United States Navy, which was developing a submarine-launched ballistic missile (SLBM), the UGM-27 Polaris. The US Chief of Naval Operations, Admiral Arleigh Burke, kept the First Sea Lord, Lord Mountbatten, apprised of its development. By moving the deterrent out to sea, Polaris offered the prospect of a deterrent that was invulnerable to a first strike, and reduced the risk of a nuclear strike on the British Isles. The British Nuclear Deterrent Study Group (BNDSG) produced a study that argued that SLBM technology was as yet unproven, that Polaris would be expensive, and that given the time it would take to build the boats, it could not be deployed before the early 1970s. The Cabinet Defence Committee therefore approved the acquisition of Skybolt in February 1960. The prime minister, Harold Macmillan, met with the president, Dwight D. Eisenhower, in March 1960, and secured permission to buy Skybolt. In return, the Americans could base the US Navy's Polaris ballistic missile submarines in the Holy Loch in Scotland. The financial arrangement was particularly favourable to Britain, as the US was charging only the unit cost of Skybolt, absorbing all the research and development costs. With this agreement in hand, the cancellation of Blue Streak was announced in the House of Commons on 13 April 1960.

The subsequent American decision to cancel Skybolt created a political crisis in the UK, and an emergency meeting between Macmillan and President John F. Kennedy was called in Nassau, Bahamas. Macmillan rejected the US offers of paying half the cost of developing Skybolt, and of supplying the AGM-28 Hound Dog missile instead. This brought options down to Polaris, but the Americans would only supply it on condition that it be used as part of a proposed Multilateral Force (MLF). Kennedy ultimately relented, and agreed to supply Britain with Polaris missiles, while "the Prime Minister made it clear that except where Her Majesty's Government may decide that supreme national interests are at stake, these British forces will be used for the purposes of international defence of the Western Alliance in all circumstances." A joint statement to this effect, the Nassau Agreement, was issued on 21 December 1962.

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