Truth and memory have a shifting relationship. At a talk about Duff Cooper’s diaries, I asked John Julius Norwich if there was any truth in a Clive James poem about his mother. It asserted, among other things, that Diana Cooper had been escorted into Paris by two dozen Spitfires, and that she carried a phial of poison ‘Against the day there was nothing left to live for’. ‘Absolute rubbish,’ he thundered from the stage. And then, ‘Oh no, wait, my daughter is waving her hand.’ She had left London with an aerial bodyguard; but the poison was a piece of poetic embroidery, his daughter said. How easily a legend springs up; how quickly the world re-edits itself as the real and the not-real weave in and out of each other.