After Joseph Stalin's death in 1953 Winston Churchill met with the United States and Soviet Union to address security and problems of the East-West relationship. The meeting took place in January 1954; no agreement was reached on Germany but a further summit was arranged in Geneva.
The Geneva summit in 1955 led to the establishment of harmonious relations between the US and China, and the resolution of conflict in the Formosa Straits. Britain was concerned about Germany and the Far East.
In 1954 radioactive atmospheric pollution from the US nuclear test at Bikini Atoll led to concerns about the health hazards of testing. Nonetheless Britain developed a thermonuclear device that was tested in 1957. In 1958 the Soviet Union announced a unilateral suspension of tests. This changed the attitude of the US government towards negotiating a test ban, and in 1958 a conference of experts met in Geneva. British representatives, particularly David Ormsby-Gore, eased negotiations concerning an inspection system between the superpowers. The Soviet representatives were opposed to onsite inspections.
Harold Macmillan also played a personal role in easing deadlocks in negotiations by visiting Moscow and Washington. It was agreed that the US, Britain and the Soviet Union would separately investigate methods of detecting underground explosions. Negotiations broke up in 1960 without an agreement, but Macmillan had persuaded Dwight D. Eisenhower to stop testing.
In July 1959, after a conference of foreign ministers in Geneva, Macmillan visited Moscow to discuss the Berlin crisis with the Soviets. Khrushchev agreed to discuss the problem at the May 1960 Paris summit, but discussions collapsed. After the Berlin crisis and the failed Paris summit, Britain's influence in East-West détente negotiations weakened.
Under John F. Kennedy the Americans worked closely with Ormsby-Gore to work out a draft treaty. In 1961, the Soviet Union decided to resume testing. The British concentrated on reaching an atmospheric ban to persuade the Americans from further atmospheric tests.
Macmillan used the testing site at Christmas Island as a bargaining tool to persuade the US to seek a test ban through the forthcoming Eighteen-Nation Disarmament Conference (ENDC). During 1962 improvements in detection technology reduced the need for onsite inspections. The outcome was a treaty proposal requiring fewer onsite inspections, but the Soviet negotiators refused again. Macmillan thought a partial ban only covering atmospheric testing might be the only chance of success.