‘This was the summer house of the first Friedrich Wilhelm,’ he said expansively. ‘And more recently the Republic used it for important guests such as the King of Egypt, and the British prime minister. Ramsay MacDonald of course, not that idiot with the umbrella. I think it’s one of the most beautiful of all the old palaces. I often walk here. This garden connects Sipo with Gestapo headquarters, so it’s actually very convenient for me. And it’s especially pleasant at this time of year. Do you have a garden, Herr Gunther?’

‘No,’ I said. ‘They’ve always seemed like a lot of work to me. When I stop work, that’s exactly what I do — stop work, not start digging in a garden.’

‘That’s too bad. At my home in Schlactensee we have a fine garden with its own croquet lawn. Are either of you familiar with the game?’

‘No,’ we said in unison.

‘It’s an interesting game; I believe it’s very popular in England. It provides an interesting metaphor for the new Germany. Laws are merely hoops through which the people must be driven, with varying degrees of force. But there can be no movement without the mallet — croquet really is a perfect game for a policeman.’ Nebe nodded thoughtfully, and Heydrich himself seemed pleased with this comparison. He began to talk quite freely. In brief about some of the things he hated — Freemasons, Catholics, Jehovah’s Witnesses, homosexuals and Admiral Canaris, the head of the Abwehr, German Military Secret Intelligence; and at length about some of the things that gave him pleasure — the piano and the cello, fencing, his favourite nightclubs and his family.

‘The new Germany,’ he said, ‘is all about arresting the decline of the family, you know, and establishing a national community of blood. Things are changing. For instance, there are now only 22,787 tramps in Germany, 5,500 fewer than at the start of the year. There are more marriages, more births and half as many divorces. You might well ask me why the family is so important to the Party. Well, I’ll tell you. Children. The better our children, the better the future for Germany. So when something threatens those children, then we had better act quickly.’

I found a cigarette and started to pay attention. It seemed like he was coming to the point at last. We stopped at a park bench and sat down, me between Heydrich and Nebe, the chicken-liver in the black-bread sandwich.

‘You don’t like gardens,’ he said thoughtfully. ‘What about children? Do you like them?’

‘I like them.’

‘Good,’ he said. ‘It’s my own personal opinion that it is essential to like them, doing what we do — even the things we must do that are hard because they seem distasteful to us — for otherwise we can find no expression for our humanity. Do you understand what I mean?’

I wasn’t sure I did, but I nodded anyway.