The thesis details the course of the civil defence debate in Britain, assesses the value of civil defence against nuclear attack and investigates other issues of concern to those involved in the debate. The thesis is divided into three parts. Part one deals with the course of the debate, the issues raised and the methods used to propogate them. The role of activists, academics and professionals is given particular emphasis. The period is charaterised as seeing the decline of civil defence, in many peoples' eyes, from a sine qua non of British defence to becoming almost an irrelevance to nuclear war. Part two, by means of the use of a reference scenario, looks in detail at the organisation and effectiveness of British civil defence against nuclear attack. It is concluded that civil defence in the long term, is unlikely to make any significant difference to the number of survivors of nuclear war. The developing knowledge and debate about the Nuclear Winter is also discussed. Part three deals with important issues in the debate which are not directly related to the effectiveness of civil defence in nuclear war. The issues, dealt with in turn, are: the current and potential effect of civil defence on civil liberties; the possible effect of civil defence on crisis stability in times of acute international tensions and the possible effectiveness of civil defence against non-nuclear attack. The conclusion offers a number of explanations as to why, given the apparent ineffectiveness of civil defence, successive governments have continued to develop it. This question is also looked at with reference to Kuhn's theory of scientific revolution and suggests that the understanding of civil defence is at present undergoing a paradigm shift. / Barrow and Geraldine S. Cadbury Trust