After moving from Harvard to the US government, Henry Kissinger said, ‘As a professor, I tended to think of history as run by impersonal forces. But when you see it in practice, you see the differences personalities make.’ The same conclusion emerges from Gill Bennett’s masterly study of six moments of crisis in British foreign policy, from the Korean War to the Falklands War. In each crisis the personalities who mattered most were not officials and special advisers but ministers, and in particular the prime minister. The more serious the crisis the greater his or her influence.

The only one of the six crises when the foreign secretary might have had the lead role was the start of the Korean War. Ernest Bevin, who held that office in the postwar Labour government led by Clement Attlee, considered himself ‘a turn in a million’. He may well have