The Zuckerman mission found the OPS useful and coming, but there was a big shock. The British were expected to contribute to the research and development costs of the A3, which dates back to 1 January 1963. These were to exceed $700 million by 1968.  Skybolt had been proposed to the United Kingdom at a unit cost, with the United States monitoring the costs of research and development, but no such agreement had been reached in Nassau for Polaris. Thorneycroft was upset by the prospect of paying research and development costs, but McNamara said the U.S. Congress would not represent an agreement that would impose all the burdens on the United States.  Macmillan asked the United Kingdom`s Ambassador to the United States, Sir David Ormsby-Gore, to inform Kennedy that Britain was not prepared to commit to spread the costs of research and development indefinitely, but would pay an additional five per cent for each missile as a compromise. He asked Kennedy to be informed that a failure of the Nassau agreement would likely cause the downfall of his government.  Ormsby-Gore met Kennedy the same day, and while Kennedy noted that the five percent offer was not “the most generous offer he had ever heard of”. McNamara, confident that the United States was scammed, calculated the five percent not only on the missiles, but also on their fire control and navigation systems, adding the bill of about $2 million. On the advice of Ormsby-Gore, this formulation was accepted. In December 1962, Harold Macmillan, then Prime Minister of the United Kingdom, met John F. Kennedy, then President of the United States, in Nassau, Bahamas.
They discussed the cancellation of the Skybolt project. Skybolt was an American development project that the United States wanted to share with the United Kingdom. It was seen as the UK`s main deterrent and its removal has raised some concerns in the United Kingdom. At that meeting in Nassau, it was agreed that the UK POLARIS A3P would be made available in order to preserve the UK`s deterrent potential in the years to come. This agreement is known as the Nassau Agreement. The U.S./U.K. POLARIS Sales Agreement was finally signed in April 1963. In addition, it was agreed that Britain would build its own submarines according to their own design, including the nuclear propulsion system, but that it would be armed with the POLARIS A3P missile. Britain would design and build its own atomic warheads for POLARIS missiles.
A U.S. mission went to the United Kingdom. It was led by Paul H. Nitze, Assistant Minister of Defence for International Security, and included Walt W.