“Look, we all know that there’s an easy way to prove who’s telling the truth here,” I said. “We should both agree to write down two names at the same time. Then you can decide for yourself what her real intentions are here, gentlemen. To help, or to hinder. If these names are not under some suspicion in the British secret service, then I’ll be the one facing a midnight boat trip, not her. I’ve already put up my hands to everything of which I’ve been accused. So, I’ve nothing at all to lose, have I? Can this beautiful lady honestly say the same?”

The monk handed me a pencil and a sheet of paper. “Very well,” he said. “I’m going to do what she’s been urging me to do for several minutes. To call your bluff. Write it down, Gunther. Write down the names. But woe betide you if you’re wrong, my German friend.”

“With pleasure.”

I tore the sheet of paper in half, wrote the name JOHN CAIRNCROSS, and handed it to the monk.

“This first man has already confessed to being a Soviet spy,” I said. “However, his name is not yet known outside of MI6. So I couldn’t possibly have known about him unless someone in the HVA had told me. Agreed?”

The monk read the name and passed it to one of his colleagues.

I prepared to write the second name, uncertain now of how to spell it. English has such peculiar, idiosyncratic spellings. The Christian name was short and obvious. But the surname was something else, like a type of felt hat beloved of English gentlemen. If I made a muck of it I was a dead man, without question. For a second or two I considered beginning the name with an “F” but changed my mind and, praying that Maugham had not mentioned to the spymasters my having listened to the conversation of Sinclair and Reilly while I was up on the roof, I wrote it with a “Ph,” like Philip. When I finished, I handed the paper back to the monk. On it was written the name KIM PHILBY.

“I suspect,” I said, “that restoring the reputation of this second man was, perhaps, what this operation was always all about.”

The monk looked at the name without betraying a flicker of recognition and then showed it to his two colleagues, whose reactions were equally gnomic.

“Now then, Miss French, I wonder if you’d mind doing the same as Herr Gunther,” said the monk, handing her the pencil and another piece of paper. “Take your time. But write down the names of anyone who was spying for the KGB in MI6, if you can.”

Anne stared at me for a moment with tight-lipped malevolence. Her early cool demeanor was gone; she’d even started biting her thumbnail.