Summary — The article examines the relationship between the leader and the party. It analizes the origins and the structure of the two main British political parties, the rules they follow for the candidate selection and for the leader election. Then it considers the different distribution of power within the Conservatives and the Labours, the relationship between the leader and the parliamentary and extra-parliamentary organizations. The Conservative party has a unitary, hierarchical structure and a deferential culture: the leader’s policy making powers are extensive and he’s responsible for the party programme His power within the party, however, is not absolute and depends on the continuing confidence of the party. The Labour party has a federal and democratjc structure and the leader has to act as a go-between among the different components of the party. The Labour extra-parliamentary organizations, first of all the Trade Unions, have an important authority.