Immediately south of Alexanderplatz, on Dircksenstrasse, the Imperial Police Praesidium and the Central Criminal Courts faced each other in an uneasy confrontation: legal administration versus justice. It was like two heavyweights standing toe to toe at the start of a fight, each trying to stare the other down.

Of the two, the Alex, also sometimes known as ‘Grey Misery’, was the more brutal looking, having a Gothic-fortress design with a dome-shaped tower at each corner, and two smaller towers atop the front and rear façades. Occupying some 16,000 square metres it was an object lesson in strength if not in architectural merit.

The slightly smaller building that housed the central Berlin courts also had the more pleasing aspect. Its neo-Baroque sandstone façade possessed something rather more subtle and intelligent than its opponent.

There was no telling which one of these two giants was likely to emerge the winner; but when both fighters have been paid to take a fall it makes no sense to stick around and watch the end of the contest.

Dawn was breaking as the car drew into Alex’s central courtyard. It was still too early for me to have asked myself why Heydrich should have had me brought here, instead of Sipo, the Security Service headquarters in the Wilhelmstrasse, where Heydrich had his own office.

My two male escorts ushered me to an interview room and left me alone. There was a good deal of shouting going on in the room next door and that gave me something to think about. That bastard Heydrich. Never quite did it the way you expected. I took out a cigarette and lit it nervously. With the cigarette burning in a corner of my sour-tasting mouth I stood up and went over to the grimy window. All I could see were other windows like my own, and on the rooftop the aerial of the police radio station. I ground the cigarette into the Mexico Mixture coffee-tin that served as an ashtray and sat down at the table again.

I was supposed to get nervous. I was meant to feel their power. That way Heydrich would find me all the more inclined to agree with him when eventually he decided to show up. Probably he was still fast asleep in his bed.

If that was how I was supposed to feel I decided to do it differently. So instead of breakfasting on my fingernails and wearing out my cheap shoes pacing round the room, I tried a little self-relaxation, or whatever it was that Dr Meyer had called it. Eyes closed, breathing deeply through my nose, my mind concentrated on a simple shape, I managed to remain calm. So calm I didn’t even hear the door. After a while I opened my eyes and stared into the face of the bull who had come in. He nodded slowly.

‘Well, you’re a cool one,’ he said, picking up my magazine.