I went to the window. I’d had very little sleep in the last three days. The lingering adrenalin of the operation had got me through the debrief, but now I was slowing up. I opened the window, took a lungful of cold air, listened to London hum. The streets were still busy, men and women walking at a measured pace, knowing their home would be there when they arrived. A Porsche accelerated away from traffic lights, radio on news, the words escalation of violence fading with its engine.

My phone rang. The GCHQ analyst said she’d run the face through every database she could and no name came up, which was conspicuous in itself these days. The Kazakh landline wasn’t on their system either.

I tried it again, and again no one answered.

I called a colleague in the Counter Terrorism section, Linda French, who had worked with Joanna.

‘Are you back?’ she asked.

‘Just in,’ I said. ‘Quick query: have you heard from Joanna Lake recently?’

‘No, I haven’t seen her for years. I heard she wasn’t with Six any more.’

‘Really?’

‘Yes.’

‘Where is she?’

‘I don’t know. What happened? Why are you back?’

I tried three other people. None had seen or spoken to her in the last five months.

Intelligence services are labyrinthine and, for obvious reasons, you can rarely see much further than the room you’re in. There isn’t a human resources department where you can knock on the door and make a polite inquiry. Not for operatives.

The ‘happy birthday’ code meant danger.

I sent a message to the TutaNota account confirming I’d received the file, asking for more information.

Meanwhile, the insurrection in Saudi Arabia that had ruined several years’ worth of my work seemed to have blown over. There’d been some arrests: clerics, intellectuals, activists accused of acting on behalf of ‘deviant groups’. Fifteen women had gathered in Jeddah, calling for the release of imprisoned relatives, surrounded by a circle of green-uniformed police holding hands so it looked like a country dance. My pyromania had disappeared from UK news.

Bohren’s phone kept flashing. I couldn’t bring myself to remove the battery but it was almost dead anyway. I sent a tentative message to the chief of Saudi Intelligence regarding my captured agent, ignored calls from a CIA contact, answered calls regarding the delivery of an artwork to Singapore FreePort, the tax-free vaults next to Changi airport that housed my agent’s embryonic collection.

‘A delivery has arrived from Christie’s New York. But we can’t get an answer regarding delivery onwards.’

‘Has it been paid for?’

‘Yes.’

‘Put it in the usual vault.’

‘Yes, sir.’