Parliament is the principal source of authority in the British political system, but it is the Cabinet which stands at the pinnacle of government and focuses our attention onto the strategies and internal divisions of our leaders. Yet the Cabinet has been neglected in terms of detailed studies of what actually happens inside its institutional walls. Historians have sometimes drawn back the veil on proceedings, en route to other destinations, but political scientists, whose professional concern it is to dissect patterns of influence and the exercise of power, have generally preferred the eclectic overview to the close-textured case-study. In particular, foreign policy has almost always been left to one side; it is as if the Cabinet's decisions on international relations are either unimportant or uncontroversial. Yet nothing could be further from the truth, as a moment's reflection on the Hoare-Laval pact, the Suez crisis or recent arguments about the European Community makes clear. What the Cabinet does and does not do in the area of foreign policy can have dramatic consequences inside and outside the state, and it is certainly not, in a still secretive political culture, an open book.

But there is no lack of materials for those prepared to venture back beyond 1960. The archives teem with relevant sources, both in the great store of public records and the private papers of innumerable former Cabinet ministers. The evolution of policy can often be studied on a day-by-day, even an hour-by-hour, basis.