Walking alongside him, Volodya said: ‘There is atonement for sin.’

Heinrich looked at him warily, as at someone who might be mad. ‘Are you a priest?’

‘You could strike back at the wicked regime you helped to create.’

Heinrich kept walking, but he looked worried. ‘Who are you? What do you know about me?’

Volodya continued to ignore Heinrich’s questions. ‘The Nazis will be defeated, one day. That day could come sooner, with your help.’

‘If you’re a Gestapo agent hoping to entrap me, don’t bother. I’m a loyal German.’

‘Do you notice my accent?’

‘Yes – you sound Russian.’

‘How many Gestapo agents speak German with a Russian accent? Or have the imagination to fake it?’

Heinrich laughed nervously. ‘I know nothing about Gestapo agents,’ he said. ‘I shouldn’t have mentioned the subject – very foolish of me.’

‘Your office produces reports of the quantities of armaments and other supplies ordered by the military. Copies of those reports could be immeasurably useful to the enemies of the Nazis.’

‘To the Red Army, you mean.’

‘Who else is going to destroy this regime?’

‘We keep careful track of all copies of such reports.’

Volodya suppressed a surge of triumph. Heinrich was thinking about practical difficulties. That meant he was inclined to agree in principle. ‘Make an extra carbon,’ Volodya said. ‘Or write out a copy in longhand. Or take someone’s file copy. There are ways.’

‘Of course there are. And any of them could get me killed.’

‘If we do nothing about the crimes that are being committed by this regime . . . is life worth living?’

Heinrich stopped and stared at Volodya. Volodya could not guess what the man was thinking, but instinct told him to remain quiet. After a long pause, Heinrich sighed and said: ‘I’ll think about it.’

I have him, Volodya thought exultantly.

Heinrich said: ‘How do I contact you?’

‘You don’t,’ Volodya said. ‘I will contact you.’ He touched the brim of his hat, then walked back the way he had come.

He felt exultant. If Heinrich had not meant to accept the proposition he would have rejected it firmly. His promising to think about it was almost as good as acceptance. He would sleep on it. He would run over the dangers. But he would do it, eventually. Volodya felt almost certain.

He told himself not to be overconfident. A hundred things could go wrong.

All the same, he was full of hope as he left the park and walked in bright lights past the shops and restaurants of Unter den Linden. He had had no dinner, but he could not afford to eat on this street.

He took a tram eastwards into the low-rent neighbourhood called Friedrichshain and made his way to a small apartment in a tenement. The door was opened by a short, pretty girl of eighteen with fair hair. She wore a pink sweater and dark slacks, and her feet were bare. Although she was slim, she had delightfully generous breasts.