‘And?’

‘And there have been little whispered conversations between Diebner and his loyal chums.’

‘Go on.’ This had to be the crunch.

‘Well, as you must know, there have been plenty of newspaper stories about the fate of Hitler. You know the sort of thing: did he really die in the bunker? Has he escaped to Spain or South America by submarine? The scientists are given the newspapers every day – and one of these stories put Diebner into a rage. “How can they print this shit?” he told the rather grim young Dr Horst Korsching. “Do they really not know where he is? God in heaven, I thought these Amis and British were brighter than that.” “Do you know where he is then, Herr Diebner?” Korsching demanded. Diebner snorted. “Of course I do. I know exactly where he is. He is in his spiritual home, waiting to rise again.” Professor Korsching pressed him. “Please, Diebner, this is big news. Won’t you tell me more?” “All I can say is, think of the Alpenfestung,” Diebner replied after a pause. “He will be protected to the death.”’

‘I see. But why trust Diebner?’

‘I have no doubts, but you’ll get to talk to him yourself, Tom. Then you can make up your own mind.’

‘Did Randy Collingham interrogate him?’

‘He couldn’t, because it was reckoned that to do so would give away the whole of Operation Epsilon. None of the scientists could be allowed to think they were being eavesdropped. Things have changed a bit since then, however. Firstly, there is the time factor. That conversation between Diebner and Korsching took place before Hiroshima and is now weeks old. Also, we have acquired the bulk of their secret knowledge – such as it is – about nuclear fission.’

‘So can we now interrogate Diebner?’

‘If we’re subtle, we can. He needs to think he’s not being picked out for special treatment, particularly not for anything he might have said, because that would be a clear indication they were being bugged. Which is why we will go in and interview each of the ten men individually. They will be told that every senior member of the former German regime now being held in POW camps and other holding centres, is being questioned about Hitler’s whereabouts. In nine of the cases at Farm Hall, we will just go through the motions. With Diebner, we will apply the third degree.’

‘It could work – if he really knows anything.’

‘There are a lot of ifs.’ Eaton began to struggle to his feet.

‘Wait. Tell me more about the Alpenfestung? The Alpine Fortress. I’ve heard of it, of course.’

‘Oh, fairy-tale stuff. The Nazis planned a vast mountain redoubt – most of the Austrian and German Alps from Feldkirch in the west to Graz in the east, and from Salzburg in the north to Villach in the south. The idea was that with a couple of SS divisions high in the mountains, Hitler and his faithful disciples could hold out for years until they were strong enough to drive down into Germany and rebuild the Reich. It didn’t quite happen like that, of course. There are no SS divisions in the Alps. That doesn’t mean Hitler doesn’t have his own little citadel there. We believe Collingham and Harper died because they had found it. Now you have to pick up the baton.’