“Convinced him to work for us instead, as a double agent. Even if we hadn’t, they’d be afraid he would break down under interrogation and compromise his handler—that’s the KGB officer who ran him—or any other agents in the network. Instead they convinced him to defect. I expect he’d been such a valuable agent, they thought he might be some use for them at Moscow Centre. KGB headquarters,” he adds.

“Yes, I know.”

“Anyway, about four years ago, Digby started showing signs of breakdown. The Soviets had broken off the network, because of some high-level defections to our side that compromised a number of their agents in the field.”

“You mean like Alger Hiss?”

“Hiss and others. You have to understand the degree of paranoia that prevails in Moscow Centre. Well, in Soviet Russia generally, but the Communist Party and the intelligence service in particular. On top of the usual backstabbings and betrayals you find in a revolutionary government, there was a series of purges in the 1930s that decimated the army and the NKVD, as the intelligence agency was then known—”

“Yes, yes. Orlovsky told me all the stories.”

“Well, it left behind a legacy of fear. Nobody trusts anybody. So when Digby found himself adrift, cut off, his guiding purpose vanished from his life—well, he went off the rails. That was the summer of 1948. We were already on his trail at that point, waiting for him to make a move. I figured that if he broke down completely, we might be able to rescue him and possibly even turn him, risky as it was.”

“But he disappeared instead,” I say. “That was when he defected, wasn’t it? In the autumn of 1948, when he vanished with Iris and the kids.”

Fox fingers the edges of the papers in his hands. “One of our agents confirmed they’d arrived in Russia in November of 1948. Seems they were first taken to a sort of secure city outside of Moscow for a year or two, to make sure they were clean—that we hadn’t turned him—and then he seems to have been given an academic job of some kind, lecturing on foreign affairs, probably doing some instruction work with the KGB.”

“How do you know all this?”

“Local assets,” he says.

“So what’s changed? Why did Iris ask me for help? And what makes you think she wants to come back home altogether?”

Fox stands and walks to the window that overlooks the courtyard. In the manner of ancient buildings, the window is a small one, the stone walls thick, so you must stand close to really look out properly. He’s still holding the envelope and the documents in one hand, while he sets them both on his hips. Someone’s opened the window to allow in some fresh air, and the smell of lemons drifts up bright and clean from the lemon tree.