The office of Prime Minister stands at the apex of the British political system. An understanding of this post is essential to all who are -- or aspire to be -- within government, or who observe it from outside. This book combines the methods of history and political science to produce theories of the development, nature and power of the premiership, and to explain the implications for present politicians and analysts. It is essential reading for for academics, students, journalists and all who are working in or interested in politics.