The eldest was a razor-sharp novelist of upper-class manners; the second was loved by John Betjeman; the third was a fascist who married Oswald Mosley; the fourth idolized Hitler and shot herself in the head when Britain declared war on Germany; the fifth was a member of the American Communist Party; the sixth became Duchess of Devonshire.

They were the Mitford sisters: Nancy, Pamela, Diana, Unity, Jessica and Deborah. Born into country-house privilege, they became prominent as ‘bright young things’ in the high society of interwar London. Then, as the shadows crept over 1930s Europe, the stark – and very public – differences in their outlooks came to symbolise the political polarities of a dangerous decade.

The intertwined stories of their lives – recounted in masterly fashion by Laura Thompson – hold up a revelatory mirror to upper-class English life before and after World War II.