ABSTRACT
The British policy of creating an independent atomic bomb was to be the main influence on atomic development through the late 1940s and early 1950s. Key decisions were dominated by the military need for plutonium. In October 1945 the Chiefs of Staff urged the government to develop an independent nuclear deterrent, rather than wait for international talks on the possible control of nuclear weapons. Of the two bombs dropped on Japan, the plutonium bomb had proved much more efficient than the uranium one. British scientists who had worked on the Manhattan Project also strongly supported the development of a plutonium weapon. It would also be cheaper to manufacture plutonium in a reactor using natural uranium than to create enriched uranium for a bomb. Enriching uranium (increasing the proportion of the fissile isotope U-235) was a major industrial process that would be costly and take several years. So the government approved the design and construction of a reactor to produce plutonium, even though the formal decision to make atomic bombs was not taken until January 1947. It was recognised that the heat inevitably generated from the reaction might be used for generating electricity but this was very much a secondary consideration (Gowing, 1974a pp. 164-166).
