‘On balance, I think this office might be the right place,’ Eaton said. He focused his gaze on Wilde. ‘Keep it businesslike from the start. Sorry, Tom.’

‘Not at all. The major’s right.’ Wilde had taken to Rittner instantly. He was efficient, professional and protective of his scientists. He would do all in his power to make their lives better, within reason, but would clearly brook no nonsense from them. A good officer.

‘I’ll make myself scarce,’ Rittner said. ‘I have worked hard to build a decent relationship with these men and I don’t want to put it in jeopardy if they become resentful. I do have one strict condition: there must be no questions of a scientific nature. Nor must they be given the slightest hint that they are being listened to by electronic means. I hope that’s clear. And please go easy on them. My professors are not war criminals; they are honourable men. Mostly, that is.’

Wilde was pretty sure that Rittner knew that Kurt Diebner was the only one who really interested them.

The major read his mind. ‘Let me mark your card regarding Herr Dr Diebner. In a word, he is cunning.’

‘Cunning as opposed to simply brilliant?’ Wilde asked.

‘Well, both of course. They’re all brilliant here. I haven’t the faintest idea what they’re talking about when they start discussing heavy water and isotopes. But of my ten professors, Diebner is the one I have least time for. Oh, he’s a charming, reasonable man to my face, but I don’t for a moment believe he is sincere. I’m convinced he knows he is being listened to. At times it seems to me that he is actually talking to the microphone, saying things he wants us to hear – excusing himself to us for his Nazi past. Trying to make out he was never really one of them, that being a party member was simply a professional necessity. It’s when he whispers that it gets interesting.’

‘Is he still a Nazi?’ Wilde asked.

The major shrugged. ‘I honestly don’t know. I’m sure you’ll find him jolly friendly, but don’t be fooled. He’d stab you in the kidneys when your back was turned. He did say he would never have anything more to do with the Nazi Party, but he was playing to the gallery. The fact is, he was a staunch party member – right up until the end. Of my ten professors, Diebner and Dr Erich Bagge were the only paid-up members of the Nazi Party.’ The major paused, then smiled wistfully. ‘There you have it – my honest opinion. I don’t like Diebner.’

*

They came in a random order and Wilde and Eaton spoke to them in a mixture of German and English, depending on their fluency. Wilde explained that the questioning was merely routine and was being applied to all senior members of the German regime currently detained by the Americans and British, which ran into hundreds of men. It was simply that the fate of Hitler had never been confirmed and they were seeking clues from anyone who might have known him or might have some clue as to his whereabouts, however tentative.