The Agreement between the United Kingdom and the United States for co-operation on the uses of atomic energy for mutual defense purposes was signed in Washington on 3 July 1958, in two original texts, the official text being English. Signatories: Hood, for London, and John Foster Dulles, for Washington. It enters into force on the date on which each Government has received from the other written notification that it has complied with all statutory and constitutional requirements: 4 August 1958. UNTS 4707, volume 326. It is not the 15 June 1955 agreement on atomic information, which it replaces, nor the 1963 Polaris Sales Agreement.

Article I: while the Parties are participating in an international arrangement for mutual defense and making substantial contributions thereto, each will communicate information and transfer materials and equipment, provided the communicating or transferring Party determines that such cooperation will promote, and will not constitute an unreasonable risk to, its defense and security. Article II provides, at framework level, for the exchange of classified information necessary to defense plans, training and evaluation; design and manufacturing methods are not described. Article V: there will be no transfer by either Party of atomic weapons; use exclusively for the preparation or implementation of defense plans in the mutual interests of the two countries.

Article III authorizes, at framework level, the sale by the United States of one complete submarine nuclear propulsion plant and agreed spare parts, for ten years after entry into force; quantities, isotopes and reprocessing are not transcribed. Article IV: responsibility for use rests with the receiving Party; the other does not warrant accuracy. Articles VI–VIII: security protection, agreed channels, no dissemination to third parties without authorization, common classification policies. Article IX: royalty-free patent licences for governmental and mutual-defense purposes, at framework level.

Article X: from entry into force, cooperation under the agreement of 15 June 1955 and paragraph B of Article I bis of the civil-uses agreement, as amended on 13 June 1956, shall be carried out in accordance with the present text. Article XII: remains in force until terminated by agreement; Article II may be terminated by either Party on one year’s notice to take effect at the end of a term of ten years, and thereafter at the end of any succeeding five-year term. Registered by the United Kingdom with the United Nations on 13 March 1959.

Cover: the United States Department of State, the place of signature; we do not claim the hall. Wikimedia Commons, free licence.

Sources consulted: US–UK Mutual Defence Agreement; UNTS 4707, Agreement for co-operation on the uses of atomic energy for mutual defense purposes.