David Lloyd George branded Sir Edward Grey, Britain’s chief diplomat for nine years before the Great War, a ‘calamitous’ foreign secretary; the newspaper controlled by Nazi Germany’s chief propagandist, Joseph Goebbels, presented him in the 1930s as ‘the gravedigger’ of the British Empire. Unusually self-aware for a politician, Grey expected history to judge him harshly, and on the whole it has.

T G Otte, a specialist in the history of prewar European diplomacy, has written the first full-length biography of Grey for sixty years in an effort to rehabilitate the Liberal politician. He has set himself a tricky challenge, because by common consent Grey was a difficult man to get to know. ‘All buttoned up’, thought Henry Campbell-Bannerman, the first prime minister to put him in the Cabinet; ‘too detached from other people’, opined his top official at the Foreign Office; an ‘always solitary man’, confided the American ambassador to his diary.

Otte nevertheless unearths a rich haul of material about the influences on his subject’s early life. Grey came from a family of Northumbrian landowners, albeit a more modest one than their neighbours the dukes of Northumberland. The family’s instincts were Whiggish; indeed, Grey’s grandfather had been a Whig home secretary