While officials on the British Nuclear Deterrent Study Group had struggled to reconcile their divergent views on the long-term form of the deterrent during 1959, Macmillan and some of his closest ministerial colleagues were considering in critical fashion the entire future nuclear weapons production programme. After a protracted process that had begun in the spring of 1958, and straddled the negotiations that led to the conclusion of the MDA, the Prime Minister had eventually given his interim agreement at the end of that year to the MoD’s plans for a wide-ranging programme involving the development and production of new megaton and kiloton-yield warheads. An important part of the rationale behind this decision was the need to keep an active and viable research and development programme at AWRE which would be sufficient to maintain the flow of exchanges that had recently been established under the MDA. The strain on the UK’s supplies of fissile material could be alleviated to a large extent by the barter arrangements over nuclear materials which formed part of the revisions to the MDA agreed by London and Washington in May 1959. However, the MoD was conscious of the need for confirmation that its production programme over the next ten years was still in need of formal ministerial endorsement. Towards the end of November 1959, Downing Street officials were duly alerted by Brundrett, the outgoing Chief Scientist at the MoD, to the need for a ministerial decision on the nuclear programme. 1