This thesis is about the growth of the anti nuclear power movement in the UK from 1955 to 1979. It seeks to explore why it emerged at the time and in the form it did. It challenges some of the existing histories and provides new explanations as to how and why, and indeed when the anti-nuclear movement emerged. It is not a policy history, but a history of activism based on accounts collected from the contemporary literature and from the activists. Its hypothesis is that an anti-nuclear power movement emerged in LTK in the 1970s because of long standing concerns of a minority over the dangers of 'atomic energy' and the continuity of opposition to the building of nuclear power stations. The divisions within the nuclear establishment over reactor choice in UK (and radiation and safety standards in US) gave new radical groups- the environmentalists - an opportunity to build a movement using new tactics of protest. The first part gives a historical account of early criticism, late 1950s protest at public inquiries, and campaigns over nuclear power from 1965 to 1979, and is based on literature surveys, interviews with anti-nuclear campaigners and research on archive material. The second part, mainly theoretical, identifies and discusses what I consider the key concepts of 'the environmental impulse', 'nuclear fear' and 'energy utopianism'. The thesis illustrates the diversity and continuity of anti-nuclear protestors, and is used to make some generalisations about their motivations and tactics, and the likelihood of future protests over new energy technologies