Glancing up as I passed through the main door, I saw a statue sitting on a truck-tyre of a scroll, working at a piece of embroidery. Flying over her head were two cherubs, one scratching his head and the other wearing a generally puzzled sort of expression. My guess was that they were wondering why the Gestapo should have chosen that particular building to set up shop. On the face of it, the art school formerly occupying number eight Prinz Albrecht Strasse and the Gestapo, who were currently resident there, didn’t seem to have much in common beyond the rather obvious joke that everyone made about framing things. But that particular day I was more puzzled as to why Heydrich should have summoned me there, instead of to the Prinz Albrecht Palais on nearby Wilhelmstrasse. I didn’t doubt that he had a reason. Heydrich had a reason for doing everything, and I felt sure that I would dislike this one just as much as all the others I’d ever heard.

Beyond the main door you went through a security check, and walking on again you found yourself at the foot of a staircase that was as big as an aqueduct. At the top of the flight you were in a vaulted waiting hall, with three arched windows that were of locomotive proportions. Beneath each window was a wooden bench of the kind you see in church and it was there that I waited, as instructed.

Between each window, on plinths, sat busts of Hitler and Goering. I wondered a bit at Himmler leaving Fat Hermann’s head there, knowing how much they hated each other. Maybe Himmler just admired it as a piece of sculpture. And then maybe his wife was the Chief Rabbi’s daughter.

After nearly an hour Heydrich finally emerged from the two double doors facing me. He was carrying a briefcase and shooed away his S S adjutant when he caught sight of me.

‘Kommissar Gunther,’ he said, appearing to find some amusement at the sound of my rank in his own ears. He ushered me forwards along the gallery. ‘I thought we could walk in the garden once again, like the last time. Do you mind accompanying me back to the Wilhelmstrasse?’

We went through an arched doorway and down another massive set of stairs to the notorious south wing, where what had once been sculptors’ workshops were now Gestapo prison cells. I had good reason to remember these, having once been briefly detained there myself, and I was quite relieved when we emerged through a door and stood in the open air once again. You never knew with Heydrich.

He paused there for a moment, glancing at his Rolex. I started to say something, but he raised his forefinger and, almost conspiratorially, pressed his finger to his thin lips. We stood and waited, but for what I had no idea.