As we moved through details – deliveries, payment chains, structures of the Qatari royal family – I kept wondering about the email contact and the missed calls. What was waiting for me on the dark web? The more my welcome home began to feel inadequate, the more this contact seemed the real business. Eventually I let the thought which I’d been fighting surface. The one other living person who knew those protocols was the officer from whom I’d inherited the agent concerned: Joanna Lake. I hadn’t seen her in six months, but the thought of a reunion had sustained me.

On a break I went outside, asked for the temporary use of my phone, then took it as far from the house as I could go without attracting suspicion. I found the last number I had for Lake and rang it, but the line was dead.

Kazakh news sites focused mostly on snowfall. There had been a storm for three days, beginning on the night of the calls. Roads were closed, whole villages had been buried. Other than that, the President had made a speech about diversifying the economy. Some industrial strikes continued. Nothing that brought the missed calls into focus.

After lunch I was interviewed by a man of around sixty with the patient, lethal air of Security Branch. He gave his name as Chris. He was curious about why I’d chosen to burn the contents of the secure room rather than bring them home as instructed. Curious about a lot of things, including my visit to the safety deposit box this morning. I humoured him, answering questions accurately, without protest. At one point, I caught him staring at my new watch. I didn’t know if he was going through the motions, reminding me of my place, or if he harboured genuine suspicions. Part of me remained in far less comfortable rooms, alongside men and women who’d risked their lives for British schemes and had been left holding empty rifles.

At three p.m., Chris departed. Undercroft and Lansdowne returned with fresh satellite images. I talked them through the towns and alliances of Syrian Kurdistan, while making my own tour of what survived, distracted by patches of new rubble.

‘They’ve destroyed the old mosque,’ I said.

I reached over and enlarged the image. A nineteenth-century mosque I’d been fond of during a brief stay in Al-Hasakah had gone, replaced by a mound of beige stone. It had been bulldozed; militiamen, enraged no doubt by the tiled calligraphy. I tried to imagine that rage. Their iconoclasm was more than just an aversion to beauty and I found it fascinating, even while the results were awful. To them, the sites themselves were blasphemous; not just art or ornament but history itself.

As we were wrapping up for the day, exhausted, I said, ‘There’s an officer who works in I/OPs: Joanna Lake. Do you have any idea of her whereabouts?’