‘I have to hand it to you,’ I said. ‘Your reasoning was perfect: find the man with the diamonds and you would find the man with the documents. And when you found out that Helfferich hadn’t hazed you, you put him on my tail. I led him to the man with the diamonds and, you thought, the documents too. At this very moment your German Strength associates are probably trying to persuade Herr and Frau Teichmüller to tell them where Mutschmann is. He’s the man who really has the documents. And naturally they won’t know what the hell he’s talking about. Red won’t like that. He’s not a very patient man, and I’m sure I don’t have to remind you of all people of what that means.’

The steel magnate stared into space, as if he had not heard one word I had said. I grabbed the lapels of his jacket, hauled him to his feet, and slapped him hard.

‘Did you hear what I said? These murderers, these torturers, have your daughter.’ His mouth went as slack as an empty douche-bag. I slapped it again.

‘We’ve got to stop them.’

‘So where’s he got them?’ I let him go and pushed him away from me.

‘On the river,’ he said. ‘The Grosse Zug, near Schmöckwitz.’

I picked up the telephone. ‘What’s the number?’

Six swore. ‘It’s not on the phone,’ he gasped. ‘Oh Christ, what are we going to do?’

‘We’ll have to go there,’ I said. ‘We could drive there, but it would be quicker by boat.’

Six sprang round the desk. ‘I’ve got a slipper at a mooring close by. We can drive there in five minutes.’

Stopping only to collect the boat keys and a can of petrol, we took the BMW and drove to the shores of the lake. The water was busier than on the previous day. A stiff breeze had encouraged the presence of a large number of small yachts, and their white sails covered the surface of the water like the wings of hundreds of moths.

I helped Six remove the green tarpaulin from the boat, and poured petrol into the tank while he connected the battery and started the engine. The slipper roared into life at the third time of asking, and the five-metre polished-wood hull strained at the mooring ropes, eager to be up-river. I threw Six the first line, and having untied the second I stepped quickly into the boat beside him. Then he wrenched the wheel to one side, punched the throttle lever and we jerked forwards.