‘They’re bugged?’

Eaton grinned. ‘Oh yes. Every bloody room. Wires in the walls, wires beneath floorboards. They can’t go anywhere without being overheard. The place was fitted out as the ultimate recording studio even before they arrived.’

‘Surely they must suspect we’re listening. I mean they are not stupid.’

‘You’d be surprised. Clever men can be astonishingly innocent to the ways of the world. Very early on, Kurt Diebner suggested to Heisenberg that perhaps they were being bugged. Heisenberg laughed the idea off. He said the British weren’t smart enough to bug them, they were too old-fashioned for such things and had learnt nothing of Gestapo methods. I suppose we should be flattered that he thinks we’re less ruthless than Hitler’s boys, but it really was very naive of him. Rather unworldly bunch, our German scientists.’

‘And have our listeners discovered much?’

‘They’ve discovered that the Germans had not progressed as far as we had feared, which was a great relief. We had to be sure that the Nazis didn’t have a bomb secreted somewhere. There is still a lot of edginess in Moscow, Washington and London regarding the possibility that Nazism isn’t quite dead and buried.’

‘But you’re saying the Germans were way behind us?’

Eaton nodded. ‘When news of Hiroshima came through, our German guests were dumbfounded. They thought it must be some kind of massive conventional device. And then, when the true nature of the bomb became known to them, they were incredulous. Utter disbelief. They had no suspicion that the Allies had got anywhere near building one.’

‘Perhaps they shouldn’t have been so hasty sacking and exiling all their brilliant Jewish physicists.’

‘Quite. But they still had some talented men – and apart from anything else we wanted to discover exactly what they knew in case their researches could be of assistance to our own scientists. Also, we wanted to keep them away from the Soviets.’

‘Ah . . . the entente looking less than cordial, is it?’

Eaton bridled. ‘Not at all. Truman alerted Stalin to the bomb when they met at Potsdam. But it’s understandable that America wants to keep its edge. That’s realpolitik.’

‘And Hitler’s part in this?’ Wilde was becoming impatient. ‘I’m pretty sure my mission as outlined to me has nothing to do with atom bombs.’

‘Indeed not. The thing is, the men inside that building have not confined themselves to talking science. They have been talking about their wives back home, the food they have been fed, the roses in the lovely Farm Hall gardens, the fate of their friends and of Germany itself – and of course their own part in it all. Much of their conversation has been pretty mundane and dull, truth be told. Most of all they have been wondering a great deal why they are being held and what is to become of them.’

Wilde sipped his tea and offered Eaton a biscuit, which he declined.

‘The scientists are mostly apolitical,’ Eaton continued, ‘so they don’t feel they are war criminals and don’t understand why they can’t go home. Some of them even appear to be rather happy that the Allies won. But not all. One of them – the aforementioned Kurt Diebner – remains a hardline Nazi, though he will deny it. A couple of others are also suspect.’