I took her to dinner at the Peltzer Grill, and then dancing at the Germania Roof, in nearby Hardenbergstrasse. The Roof was crowded with Berlin’s smartest set, many of them in uniform. Inge looked around at the blue glass walls, the ceiling illuminated with small blue stars and supported with columns of burnished copper, and the ornamental pools with their water-lilies, and smiled excitedly.

‘Isn’t this simply wonderful?’

‘I didn’t think that this was your sort of place,’ I said lamely. But she didn’t hear me. She was taking me by the hand and pulling me on to the less crowded of the two circular dance-floors.

It was a good band, and I held her tight and breathed through her hair. I was congratulating myself on bringing her here instead of one of the clubs with which I was better acquainted, such as Johnny’s or the Golden Horseshoe. Then I remembered that Neumann had said that the Germania Roof was one of Red Dieter’s chosen haunts. So when Inge went to the ladies’ room I called the waiter over to our table and handed him a five.

‘This gets me a couple of answers to a couple of simple questions, right?’ He shrugged, and pocketed the cash. ‘Is Dieter Helfferrich in the joint tonight?’

‘Red Dieter?’

‘What other colours are there?’ He didn’t get that, so I left it. He looked thoughtful for a moment, as if wondering whether or not the ringleader of German Strength would mind his being identified in this way. He made the right decision.

‘Yes, he’s here tonight.’ Anticipating my next question, he nodded over his shoulder in the direction of the bar. ‘He’s sitting in the booth furthest from the band.’ He started to collect some empties from the table and, lowering his voice, added, ‘It doesn’t do to ask too many questions about Red Dieter. And that’s for free.’

‘Just one more question,’ I said. ‘What’s his usual neck-oil?’ The waiter, who had the lemon-sucking look of a warm boy, looked at me pityingly, as if such a question hardly needed to be asked.

‘Red drinks nothing but champagne.’

‘The lower the life the fancier the taste, eh? Send a bottle over to his table, with my compliments.’ I handed him my card and a note. ‘And keep the change if there is any.’ He gave Inge the once-over as she came back from the ladies’ room. I didn’t blame him, and he wasn’t the only one; there was a man sitting at the bar who also seemed to find her worthy of attention.

We danced again and I watched the waiter deliver the bottle of champagne to Red Dieter’s table. I couldn’t see him in his seat, but I saw my card being handed over, and the waiter nodding in my direction.