‘Must be six months,’ responded the other. ‘Don’t buy another one, this isn’t a charity you know.’ He probably said that several times a day. Coathanger blinked with slow boredom.

‘See what I mean? Look, go somewhere else if you think you can get more for it.’ But the sight of the cash was too much for the old man, and he capitulated. I walked to the head of the line and said that I was looking for Herr Neumaier.

‘If you’ve got something to sell, then you’ll have to wait in line with all the rest of them,’ muttered Coathanger.

‘I have nothing to sell,’ I said vaguely, adding, ‘I’m looking for a diamond necklace.’ At that Coathanger smiled at me like I was his long-lost rich uncle.

‘If you’ll just wait one moment,’ he said unctuously, ‘I’ll just see if Herr Neumaier is free.’ He disappeared behind a curtain for a minute, and when he returned I was ushered through to a small office at the end of the corridor.

Peter Neumaier sat at his desk, smoking a cigar that belonged properly in a plumber’s tool-bag. He was dark, with bright blue eyes, just like our beloved Führer, and was possessed of a stomach that stuck out like a cash register. The cheeks of his face had a red, skinned look, as if he had eczema, or had simply stood too close to his razor that morning. He shook me by the hand as I introduced myself. It was like holding a cucumber.

‘I’m pleased to meet you, Herr Gunther,’ he said warmly. ‘I hear you’re looking for some diamonds.’

‘That’s correct. But I should tell you that I’m acting on behalf of someone else.’

‘I understand,’ Neumaier grinned. ‘Did you have a particular setting in mind?’

‘Oh, yes indeed. A diamond necklace.’

‘Well, you have come to the right place. There are several diamond necklaces I can show you.’

‘My client knows precisely what he requires,’ I said. ‘It must be a diamond collet necklace, made by Cartier.’ Neumaier laid his cigar in the ashtray, and breathed out a mixture of smoke, nerves and amusement.

‘Well,’ he said. ‘That certainly narrows the field.’

‘That’s the thing about the rich, Herr Neumaier,’ I said. ‘They always seem to know exactly what they want, don’t you think?’

‘Oh, indeed they do, Herr Gunther.’ He leaned forwards in his chair and, collecting his cigar, he said: ‘A necklace such as you describe is not the sort of piece that comes along every day. And of course it would cost a great deal of money.’ It was time to stick the nettle down his trousers.

‘Naturally, my client is prepared to pay a great deal of money. Twenty-five per cent of the insured value, no questions asked.’

He frowned. ‘I’m not sure I understand what you’re talking about,’ he said.