In my mother’s final days we had a long conversation about the second world war. I asked if she’d ever thought we might lose. ‘No,’ she snapped. ‘I knew we were too clever for them.’

The chief of the imperial general staff, Sir Alan Brooke, had been less sanguine. On 31 March 1942 he confided to his diary: ‘During the last fortnight I have had, for the first time since the war started, a growing conviction that we are going to lose.’