‘I don’t think they’re that imaginative,’ I said.

‘They chose us because we were already halfway corrupt.’

*

I turned Cherenkov’s business card in my hand again and wondered what light he could throw on Perfect Vision, and what I’d have to do to get it. Be careful, I thought. Exhaustion had begun to fog my judgement. I wasn’t going to sleep, so I went for a walk.

The roads had iced. I took my gloves off and touched the hard snow. It was what Mongolians called a harin zud, a black freeze, when snowfall was followed by another sudden drop in temperature. The earth became inaccessible. Out on the steppe it spelled the death of livestock in their thousands. I’d been told of horses eating their own hair. People died but it was impossible to dig graves, so they were mummified until summer, organs replaced with pine needles and larch cones. In Astana it meant drivers kept to 10 miles per hour, like a city-wide funeral procession. Near Bayterek I saw three crashed cars, one on its side, strands of emergency tape fluttering.

The colours of the office blocks changed from green to blue. There was an unearthly metallic ticking sound that I eventually identified as streetlights agitated in the wind. I got the war-zone feeling, where everything seems provisional, and when you look at buildings you see their destruction too.

Who else was chasing this imminent attack? I didn’t feel in a position to take responsibility for stopping it. Reza was good, but he had more allies in Peshawar than Washington. When Joanna needed access to northern Syria I introduced them. We met in the closest he had to an office – which was someone else’s office behind five walls of concrete and barbed wire. There was a poster of an imaginary Kurdistan on the wall, a photograph of a young-looking Reza with Bill Clinton. Joanna was all charm and only gave me her opinion of him on the flight back: she said he was well connected and borderline insane. The CIA, she felt sure, kept him active in the hope that he’d get himself killed.

I’d first bumped into him in Tajikistan, the most lawless corner of Asia at that time, controlled by a circus of Russian soldiers, Islamist guerrillas, warlords, bandits and deserters from all sides. It was 90 per cent mountain rock. The only way to make a living was by trading weapons or narcotics. Russia had established outposts along the border, then manned them with drunks and criminals, whiling away long hours as they waited to be decapitated by insurgent Afghans.