His real father had died a year before that, drowned, after a well-publicised incident on the cruise liner, Andromeda, off Madagascar. One witness had insisted that Mr Blitz had ‘recklessly and with aforethought’ hurled himself over the rail of the quoits deck into the Indian Ocean, and had swallowed enough water to sink himself before the ship could be brought about. But Mrs Blitz had strenuously denied any suggestions of suicide. Her husband had been ‘in bustling health’, she had told the coroner, prettily, and he had been eager to start up a new property business in Cape Town.

But now Peter was here, in the big redbrick house in Montacute Road, overlooking a tired triangle of grass and plane trees, with his mother’s jewellery case open in front of him, and a diamond between his fingers that was bigger than he would have thought possible. It had to be real, he was convinced of it, even though he had no expertise in diamonds, and no means of testing the stone, apart from using it to scratch his name on the bedroom window, which somehow did not seem like a very reverent idea. In the five years since his stepfather had died, Peter had gradually become aware that the love between his mother and his real father had been something intense, and very special, and that even their eventual separation had not been able to extinguish it.

If the love between his mother and his real father had been only half as fierce as his mother had described it (and being a modest woman, a vicar’s widow, it had probably been twice as passionate, and twice as jealous as she had told him), then this diamond which symbolised it just had to be authentic, and flawless, too.

His mother’s maid, Olive, came into the bedroom, with a japanned carpet sweeper, her hair a chaos of henna-stained curls and tortoise-shell combs. ‘It wouldn’t be disrespectful to open the curtains, do you think, sir?’ she suggested. ‘I would hate to think of you straining your eyes. My ’enry strained his eyes, fighting in the dark at Nicholson’s Nek.’

Peter clasped the diamond protectively in both hands, and turned around in a way that was stiffer and more mannered than he would have liked. ‘By all means draw them,’ he said. ‘I don’t think Mother would have wanted to see the house so gloomy in any case, do you?’

Olive drew back the thick brocade drapes with a rattle of brass rings. The London sunlight fell across the patterned rug, and on to the white-covered bed on which only a fortnight ago his mother had closed her eyes for the last time, as if asleep. On the wall beside the bed hung a plain wooden crucifix: his mother used to tell Peter that she had been given it by a missionary in South Africa, when she was still a young girl — before she could even speak English.