It was only when I got out of the car that I noticed the large dark-blue Mercedes convertible parked about twenty metres down the street, and the two men who were leaning on it, waiting for someone. I braced myself as one of the men threw away his cigarette and walked quickly towards me. As he drew nearer I could see that he was too well-groomed to be Gestapo and that the other one was wearing a chauffeur’s uniform, although he would have looked a lot more comfortable in a leopard-skin leotard, with his music-hall weightlifter’s build. His less than discreet presence lent the well-dressed and younger man an obvious confidence.

‘Heir Gunther? Are you Herr Bernhard Gunther?’ He stopped in front of me and I shot him my toughest look, the sort that would make a bear blink: I don’t care for people who solicit me outside my house at one in the morning.

‘I’m his brother. He’s out of town right now.’ The man smiled broadly. He didn’t buy that.

‘Herr Gunther, the private investigator? My employer would like a word with you.’ He pointed at the big Mercedes. ‘He’s waiting in the car. I spoke to the concierge and she told me that you were expected back this evening. That was three hours ago, so you can see we’ve been waiting quite some time. It really is very urgent.’

I lifted my wrist and nicked my eyes at my watch.

‘Friend, it’s 1.40 in the morning, so whatever it is you’re selling, I’m not interested. I’m tired and I’m drunk and I want to go to bed. I’ve got an office on Alexanderplatz, so do me a favour and leave it till tomorrow.’

The young man, a pleasant, fresh-faced fellow with a buttonhole, blocked my path. ‘It can’t wait until tomorrow,’ he said, and then smiled winningly. ‘Please speak to him, just for a minute, I beg you.’

‘Speak to whom?’ I growled, looking over at the car.

‘Here’s his card.’ He handed it over and I stared stupidly at it like it was a winning raffle-ticket. He leaned over and read it for me, upside-down. ‘“Dr Fritz Schemm, German Lawyer, of Schemm & Schellenberg, Unter den Linden, Number 67.” That’s a good address.’