Next day we drove along the border with Afghanistan. I’d earned his trust. We skirted the most beautiful and dangerous scenery I’d seen, mountains folded around poppy fields. We followed a two-lane road towards China. When we were a hundred miles or so from anything, Reza sat me down and we talked networks, funding programmes, his plans for the region. He wanted to know what I thought, and what support I could get. It seemed a bit crazy, knocking around foreign policy on a mountainside littered with smashed cars, although it doesn’t seem so crazy now. On the way back he stopped in at a mud-walled village, ‘dropping off provisions’. While he chatted up locals, I looked inside the remaining parcels on the back seat of his car. They contained encrypted radios and body armour.

By the following week we were solid friends. In 2013 he began making noises about support for rebel militias: Libya initially, then Syria. Asked for you by name, Kane. Kurdish-led Syrian Defence Forces, he said: they’re our men. They’ve got the fighters, Saudis have the money. Boom.

He linked Joanna up with some Kurdish cigarette smugglers based in Qamishli, a Syrian city near the Turkish border. She had been suspicious before meeting him, then disarmed by his charisma – and more suspicious. I had mentioned him the last time we met, a conversation the three of us had had about emotional manipulation. I’d used him as an example of what you can’t do with computers. ‘He’s mad, but he understands grievances.’

‘There’s software for that,’ she’d said.

Joanna and I argued, in a fairly civil way at first, about psychology: a nation’s psychology and the limits of computing; historical and cultural sensitivity – trauma, resentment – how would a machine learn that? Feed in artworks, school lessons, poetry, I suggested, jokingly; dreams, nightmares.

‘Why not,’ she said.

GCHQ had a program called XKeyscore which had already hoovered up data for entire populations, including medical records. It consisted of over 700 servers at approximately 150 sites. The data came from satellite intercepts, telecoms access, and what they called overhead: pickup from planes and drones. There was third-party product from twenty-seven countries, content and metadata. Like a lot of industries, the challenge facing the intelligence services wasn’t getting all this information, it was figuring out what to do with it. You’ve got every word used in phone calls, emails and messaging services in Georgia over a twelve-month period. How do you turn that into knowledge? How can you accept that it doesn’t tell you the future?

‘So what’s next?’ I asked. Part of me was getting sucked in, wondering if maybe Joanna and her secretive Shefford unit really had glimpsed something ahead.

She said there would be another incident like the Crimea. Russia wouldn’t sit still. We argued about that. I said the risks were too high.

‘You don’t think they would?’