Anglo-American nuclear relations from the mid-1950s on are marked by Britain's attempt to sustain its international significance as a Great Power even while it depended on a sustained flow of US nuclear secrets to build an ‘independent’ nuclear deterrent that could contribute usefully to the defence of Western Europe. A study of Anglo-American debates over the proliferation risks of gas-centrifuge enrichment in the late 1960s provides an ideal case study to illustrate the persistence of the tensions over the exchange of sensitive knowledge in the ‘civilian’ domain that had dominated the earlier negotiations over weapons science and technology. The United Kingdom, as one of the primary signatories of the Nuclear Non-Proliferation Treaty, thought it crucial to alert Washington to the dangers to the treaty posed by a revolutionary new enrichment process that threatened to ‘democratise’ the production of fissile material. US officials did not share their anxieties. Their major concern was to protect their technological lead and to use it as a political weapon to hem in Britain and those European allies who were developing gas-centrifuge enrichment. The British were once more made aware of the inequality inscribed in the special nuclear relationship deriving from the United States’ technological superiority.
