‘Should we tell him you said that?’ Wilde asked.

‘Tell him what you like. He is a despicable man.’

Wilde could see the strain in Heisenberg’s eyes. This confinement was taking a toll on him. ‘Is everything all right, Professor?’ he asked. ‘These must be difficult days for you.’

‘Yes, it is hard for all of us. The hardest thing was learning that the Americans were so far ahead of us with their device. They made us look small and backward. We were all astonished when we heard about the bomb in Japan. In Germany, we were nowhere near . . .’

‘Were you really trying?’ Wilde said, then remembered the stricture: no science. ‘Forget I asked that,’ he said. For a moment, he felt for the man. He knew how humiliated Heisenberg had been by America’s success and his own failure; Otto Hahn had been recorded calling him a second-rater, to his face. Perhaps the truth was that he, Heisenberg, was surrounded by second-raters.

‘One more thing,’ Eaton said. ‘We know you never joined the Nazi Party, but you wanted Germany to win the war. That would have made the Nazis all-powerful, would it not?’

‘I didn’t want them to beat the West, but I wanted them to destroy Bolshevism.’

Wilde and Eaton looked at each other. Wilde could no longer bear to listen to the man’s triangulation. Heisenberg had had every opportunity to leave Germany before the war, but had chosen to stay. ‘Thank you, Professor,’ Wilde said. ‘That will be all.’

Heisenberg rose from his chair. ‘Then I shall go back to my reading in the rose garden. It has been a pleasure to meet you two gentlemen. Life here is very tedious and anything that breaks up the monotony is welcome. I just want to get back to my work.’

Kurt Diebner was the third man to arrive.

He had a smooth, unprepossessing face and sloped forehead, a little like Himmler, but without the moustache. His hair was brushed back severely, flat to his head, and he wore round spectacles.

His eyes shifted between his two interrogators, seeking clues as to their significance, and the nature of the meeting.

‘Take a seat, Dr Diebner,’ Wilde said. Eaton had warned him to go easy on the man because he had threatened suicide in the past, but Wilde wasn’t about to hold back. He wanted to be in control of this interview. ‘I am Thomas Wilde, and my colleague is Mr Philip Eaton.’

‘Good day to you, gentlemen,’ Diebner said.

‘And to you, Doctor. This is a straightforward chat and one that is being conducted with all senior members of the late German administration. As you can imagine, there is much interest in the fate of Adolf Hitler. Is he dead or is he alive – and if he is alive, where is he?’

‘Of course. I can understand why you need to know that.’

‘So we have a simple question for you all: do you have any information that might be able to assist us?’