‘All the same, I’m very sorry,’ said Samuel.

‘Thanks,’ said Peter, trying to brighten up.

‘Won’t you come through to the back?’ asked Samuel. ‘I have some tea left in the pot, and some capital veal pie.’

He lifted the mahogany flap of the counter, and Peter followed him through into a dark back room, where there was a badly dilapidated sofa, a fireplace still clogged with last winter’s ashes, and a jeweller’s workbench, cluttered with silver wire and forceps and soldering irons. On the wall was a saucy calendar of a naked theatre girl with plumes of ostrich feathers in her hair and strings of pearls around her ankles.

‘I don’t suppose you’ve seen anything of Walter,’ said Samuel, taking the lid off the teapot and peering into it suspiciously.

‘Not a peek. I heard he went off to Malaya to plant rubber.’

‘He always did have the look of a rubber-planter, I must admit.’

Peter moved four or five tattered copies of The London Illustrated News from the sofa, and sat down. ‘I don’t know. What does a rubber-planter look like?’

Samuel shrugged. ‘Rubbery, I suppose. Shall I brew some fresh?’

‘Don’t bother. What I really came about was more in the line of business.’

‘I see,’ said Samuel, sitting down. He cut a piece of veal pie off a twenty-one pound slab, and pushed it into his mouth. ‘I suppose your poor mama left you quite a bit of disposable jewellery?’

‘I haven’t been through it all yet,’ Peter told him. ‘But I was mainly concerned about this,’ and he produced from his pocket the small drawstring purse, which he loosened, and then turned upside-down over Samuel’s workbench.

The diamond rolled out on to the bench, and lay on its side, sparkling in the gaslight. Samuel, his mouth still stuffed with pie, stared at it as if God had just dropped a third tablet of commandments from the heavens above.

‘What on earth …?’ he asked. ‘You’re not telling me that’s a real stone?’

Peter nodded. ‘I’m pretty well convinced of it.’

‘But that’s a diamond,’ said Samuel. ‘You don’t find diamonds in that sort of size. That’s as big as the Regent. Bigger. It can’t be real. Where on earth did you get it?’

‘My mother’s jewellery box.’

‘Not even in a safe? It can’t be real. My dear chap, if that were a real diamond, it would be worth … a million pounds. Maybe more. You wouldn’t keep it in a jewellery box. You’d have it locked up, in Coutts.’

‘Maybe you would, and maybe you wouldn’t. What burglar would ever suspect that a vicar’s wife would have a million-pound diamond in her jewellery box? A couple of rings, maybe; a pinchbeck pendant. But not a million-pound diamond.’

Samuel picked the diamond up and frowned at it. Then he reached for his jeweller’s loupe, his 10 × magnifying lens, and peered at it even more closely.