He’d stayed awake all night: dawn came and passed, and the first Monday of October, which was a day he’d been fated never to see, was spent in his cell. The guards constantly checked him and Kiselyov came in two or three times to assure him he was about to be transferred to another block, but that was still being sorted and he should be patient.

He’d begun to doubt it would ever happen, but then at eight o’clock that night, the cell door opened and Kiselyov told him to get a move on. He was handcuffed and shackled and led through Block D, by which time of course the other prisoners had been locked down and the lights in the corridors and halls dimmed. When they came to the entrance to the block, he was told to wait and a hood was placed over his head; he was convinced this meant they were about to shoot him, or worse still, hang him, which he considered a far worse fate. As he was hurried across a courtyard and along a rough path and then into another block, he wondered why they needed to go to all this trouble if they were going to kill him.

The cell they took him into was the least unpleasant of the half-dozen or so he’d been in at Hohenschönhausen. It was quite large, with a toilet and a sink in one corner, which made a welcome change from the bucket and bowl he’d been used to. It also contained two beds, and to his surprise, a man in prison uniform was sitting on one of them.

‘Reinhard Möller.’ The other man had waited until the guards had locked the door and turned off the light before getting up and shaking Schweitzer’s hand in a friendly manner. He apologised for not being very talkative but said he was tired. ‘I’ll introduce myself properly in the morning.’

Three days earlier – on the Saturday morning – back at RAF Gatow in the south-west of Berlin, an irritated Bemrose was waiting outside in the Humber Snipe, muttering that he still resented being treated as a chauffeur but that when he’d complained to Mr Gilbey, he’d been told how important this job was.

In the arrivals area, Hanne and Prince watched as the RAF Dakota landed somewhat awkwardly, bouncing on the runway as it was buffeted by a cross-wind and then taxiing towards the apron.

The two men they were waiting for greeted them warmly. Tom Gilbey said he couldn’t believe the destruction he’d seen as the plane descended over Berlin. The other man said he could. ‘It’s far worse on the ground, I can tell you – remember, I was only here five months ago. I lived through the Battle for Berlin!’

The conversation in the car from the airport to the safe house Bemrose had organised in Wilmersdorf was restricted to the weather and the areas they were driving through. The German who’d arrived with Gilbey apologised. ‘I could give you a guided tour, but it’s so hard to recognise places.’