The photograph facing page seventy-six of Lady Mosley’s book would not be in the least extraordinary if the caption ‘Derek and Pam at Caxton Hall, 29 December 1936’ were not appended. It is, of course, a still from a Hollywood movie, perfectly lit and posed, with easily identifiable stars. The glowering old boy on the right is C Aubrey Smith as Lord Redesdale: flanking Derek the groom (Claud Rains, natch) is Mary Astor who plays Muv as a vampire-harpy hybrid. Franchot Tone, in the unrewarding role of Tuddemy, looks soulfully into the camera, while Olivia de Haviland as Nancy contemplates the middle distance with the enigmatic air of one who might have landed her catch with a touch more effort. Pam, it goes without saying, is Bette Davis, but who is the Garboesque blonde up left? ‘Promising newcomer’ is hardly the word for Diana Mosley, whose handsomely illustrated pen portraits of her chums remind us that, more than some, she has knocked about and seen a bit.

Mitfordiana has become a cultural subspecies. That obsessive English passion for snooping and prying into the lives of others has been rewarded for the past thirty years with the pranks, scrapes and wheezes of Decca, Debo, Boud and the rest, the most successful family self-marketing enterprise of the century. The