page_title: Polaris Sales Agreement
section_title: Negotiations
hierarchical_section_title: Polaris Sales Agreement / Negotiations
caption_attribution_description: English: KN-C19267. President John F. Kennedy Meets with the Ambassador of Great Britain, Sir David Ormsby-Gore
context_page_description: The Polaris Sales Agreement was a treaty between the United States and the United Kingdom which began the UK Polaris programme. The agreement was signed on 6 April 1963. It formally arranged the terms and conditions under which the Polaris missile system was provided to the United Kingdom.
  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.
context_section_description: With the Nassau Agreement in hand, it remained to work out the details. Vice Admiral Michael Le Fanu had a meeting with the United States Secretary of Defense, Robert S. McNamara, on 21 December 1962, the final day of the Nassau conference. He found McNamara eager to help, and enthusiastic about the idea of Polaris costing as little as possible. The first issue identified was how many Polaris boats should be built. While the Vulcans to carry Skybolt were already in service, the submarines to carry Polaris were not, and there was no provision in the defence budget for them. Some naval officers feared that their construction would adversely impact the hunter-killer submarine programme. The First Sea Lord, Admiral of the Fleet Sir Caspar John, denounced the "millstone of Polaris hung around our necks" as "potential wreckers of the real navy".
  The number of missiles required was based on substituting for Skybolt. To achieve the same capability, the BNDSG calculated that this would require eight Polaris submarines, each of which would have 16 missiles, for a total of 128 missiles, with 128 one-megaton warheads. It was subsequently  decided to halve this, based on the decision that the ability to destroy twenty Soviet cities would have nearly as great a deterrent effect as the ability to destroy forty. The Admiralty considered the possibility of hybrid submarines that could operate as hunter-killers while carrying eight Polaris missiles, but McNamara noted that this would be inefficient, as twice as many submarines would need to be on station to maintain the deterrent, and cautioned that the effect of tinkering with the US Navy's 16-missile layout was unpredictable. The Treasury costed a four-boat Polaris fleet at £314 million by 1972/73. A Cabinet Defence Committee meeting on 23 January 1963 approved the plan for four boats, with Thorneycroft noting that four boats would be cheaper and faster to build.
  A mission led by Sir Solly Zuckerman, the Chief Scientific Adviser to the Ministry of Defence, left for the United States to discuss Polaris on 8 January 1963. It included the Vice Chief of the Naval Staff, Vice Admiral Sir Varyl Begg; the Deputy Secretary of the Admiralty, James Mackay; Rear Admiral Hugh Mackenzie; and physicist Sir Robert Cockburn and F. J. Doggett from the Ministry of Aviation. That the involvement of the Ministry of Aviation might be a complicating factor was foreseen, but it had experience with nuclear weapons development. Mackenzie had been the Flag Officer Submarines until 31 December 1962, when Le Fanu had appointed him the Chief Polaris Executive (CPE). As such, he was directly answerable to Le Fanu as Controller of the Navy. His CPE staff was divided between London and Foxhill, near Bath, Somerset, where Royal Navy had its ship design, logistics and weapons groups. It was intended as a counterpart to the United States Navy Special Projects Office (SPO), with whom it would have to deal.
  The principal finding of the Zuckerman mission was that the Americans had developed a new version of the Polaris missile, the A3. With a range extended of 2,500 nautical miles (4,600 km), it had a new weapons bay housing three re-entry vehicles (REBs or Re-Entry Bodies in US Navy parlance) and a new 200-kilotonne-of-TNT (840 TJ) W58 warhead to penetrate improved Soviet anti-missile defences expected to become available around 1970. A decision was therefore required on whether to purchase the old A2 missile or the new A3. The Zuckerman mission came out in favour of the new A3 missile, although it was still under development and not expected to enter service until August 1964, as the deterrent would remain credible for much longer. The decision was endorsed by the First Lord of the Admiralty, Lord Carrington, in May 1963, and was officially made by Thorneycroft on 10 June 1963.
  The choice of the A3 created a problem for the Atomic Weapons Research Establishment (AWRE) at Aldermaston, for the Skybolt warhead that had recently been tested in the Tendrac nuclear test at the Nevada Test Site in the United States would require
caption: President John F. Kennedy meets with the British Ambassador to the United States, Sir David Ormsby-Gore, in the Oval Office.
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