On 17 February 1958, 5,000 people crammed into Central Hall, Westminster, and three overflow halls for the launch of CND; a thousand were turned away. The following day several hundred supporters sat down in Downing Street. From its first public moment, CND became a mass movement rather than the elite pressure group that most of its founders envisaged. That Easter saw the first Aldermaston march from central London to the atomic weapon research establishment – from the following year, the direction would be reversed. Public meetings were held in many cities and towns, so that by the end of the year there were over 200 local groups, as well as women’s, scientists’, artists’, regional and youth sections. In 1959, CND expanded much further and by 1960 there were 459 groups. In August that year, the conference of the opposition Labour Party adopted unilateral nuclear disarmament as its policy. In two and a half tumultuous years, the new movement had brought nuclear weapons to the forefront in Britain, changing the face of its politics and culture, in some ways for ever.

The crisis of the late 1950s

This outbreak of antinuclear politics was, in retrospect, well prepared. The years after the bombing of Japan saw frightening new international tensions in which Britain was heavily involved, from the 1948–9 Berlin Blockade to the 1950–3 Korean War. The possibility of nuclear war became a part of British life, and in this pre-H-bomb phase, the government actively prepared the public for it: annual publicity campaigns brought half a million people into the Civil Defence Corps by 1955 (Grant 2009: 4–5, 2016: 92–4). Although concern about atomic weapons was expressed by the Peace Pledge Union in 1945 and gradually grew in the late 1940s and early 1950s, the focus of pacifist, liberal and left-wing circles was mostly on other repercussions of the Cold War, such as the reintroduction of conscription in 1948, Britain's involvement in Korea and German rearmament in 1954. Quite a few of those who would warn of nuclear dangers in the late 1950s were content to accept them in the 1940s (Sedgwick 1959: 7).