The 1958 Mutual Defence Agreement and the 1980 Trident Decision

Much has been written on the “special relationship” Britain has with the United States. Much less has been written on their “special nuclear relationship” created by the signing of the Mutual Defense Agreement(MDA) in 1958 and its 1959 amendments. These agreements on warhead and materials exchanges were supplemented in 1963 by the Polaris Sales Agreement (PSA), a deal concluded following the cancellation of the U.S. Skybolt air-delivered nuclear missile to be supplied to the United Kingdom. The PSA extended arrangements existing under the MDA to assist the United Kingdom in procuring the latest U.S. means of strategic nuclear delivery. Both agreements were essential to negotiations in 1979 and 1980 for the sale of the U.S. Trident submarine-launched ballistic missile (SLBM) system to Britain.