This work investigates the evolution and functional mechanics of the office of the Prime Minister within the British constitutional framework. Robert Blake, a noted historian and peer, utilizes his expertise in British political history to trace the development of executive power over two and a half centuries. He examines the shifting power dynamics between the Prime Minister, the monarchy, the Cabinet, and the legislative houses to explain how the role attained its modern authority.

Experts recognize this text as a foundational study for understanding the development of the British executive branch. Readers frequently note the clarity of the prose despite the complex constitutional subject matter.