The thesis is concerned with the organisational and ideological development of the Monday Club and its contribution to the Conservative Governments, the Conservative Party and the modern British Right, from the Club's inception in 1961 to the fall of Margaret Thatcher in 1990. The significance of this investigation lies in the fact that whilst the Monday Club is much referred to, with the exception of one article, it has not been seriously studied. Yet, it has been regarded as one of the most well known groups within the Conservative Party and it was important enough for a number of Conservative MPs, including members of the Cabinet, to have become members. The Monday Club is most frequently associated with controversial views on decolonisation and immigration, and these are explored in some detail. However, it adopted a comprehensive policy framework which the thesis addresses by looking at a range of policy areas. The thesis shows that the Club activity was intended to influence the Conservative Party and the British Right. However, while it has been claimed that the Club has influenced the Conservative Party or Conservative Government policy, the thesis argues that where Conservative policy has accorded with that of the Club, this was crucially where it shared ground with other groups on the New Right. The study has also considered the novelty of the Club's conservatism. It espoused a particular kind of conservatism, which is best classified as radical right, a development that left it outside the main forces driving Conservatism and Britain to the right in the closing decades of the twentieth century. The thesis has particularly drawn on Monday Club publications, a number of interviews and access to a hitherto unused archive, the Sir Patrick Wall collection of papers, held at Hull University.