Date

Jun 8, 1958

Description

Reached after a long negotiating process, this agreement on nuclear retaliation procedures stemmed from direct pressure from Prime Minister Macmillan for a detailed formal accord governing U.S. and British decisions to initiate such a launch. The agreement enshrined an understanding that had been first reached in October 1951that the use of nuclear weapons from U.S. bases in the United Kingdom would be a matter of “joint decision.” While British leaders also wanted to be consulted on U.S. decisions to use nuclear weapons generally, from the U.S. perspective that would depend on the "circumstances prevailing at the time," reflecting U.S. insistence on freedom of action.[10]

The Murphy-Dean agreement established a protocol for future consultations. If circumstances permitted a conference call between the president and the prime minister, the agreement spelled out the process of decision that would occur under two different situations: 1) strategic warning (longer-term warning of attack) and tactical warning ("short warning of imminent attack derived from positive radar or other means"). Strategic warning could permit a decision to launch a preemptive assault on Soviet nuclear forces, although whether any warning would be certain enough to allow such a grave decision has been a matter of debate for many years. In the event of tactical warning, military commanders could launch forces under "positive control" (also known as "fail safe”); thus U.S. and British bombers would fly to a "specified line" but would not pass beyond it without receiving definite instructions.

Previously excised from an earlier declassification are passages concerning the British chain of decisions as well as references to nuclear weapons of U.S. origin that had been provided secretly through “Project E.” The British decisions concern what the prime minister and the chief of the Air Staff would do in event of strategic warning or tactical warning. For example, among the decisions that the prime minister and the U.S. president would have to agree upon was whether an attack, preemptive or retaliatory, would include weapons of U.S. origin, which would be used by Thor IRBMs and the British medium bomber force. The details of the agreement would be modified over time owing to changes in U.S. delivery systems and weapons deployed in the United Kingdom and changes in targeting responsibilities.[11]

Source

RG 59, Central Decimal Files, 1955-1959, 741.5611/6-858 (released on appeal)

Document published in following posting(s):

The British Bomb and the United States - Part One

May 13, 2021