‘To see if you’re as dark and troubled as they are, perhaps. I don’t know. It made sense at the time. When they can, the officers pair friends, brothers, get them to knock each other unconscious.’

‘Lovely. Why did you choose the Paras?’

‘More class-free, less hierarchical.’

‘And you ended up in Six.’

‘I know.’

Joanna was the only person I had told any of this. I remember, at the time, thinking we were old. We were twenty-four. We survived several years’ acquaintance before succumbing to the inevitable. Other partners helped. Joanna used to say: this one had better work or we will end up together. It was a joke and not a joke, brought to comic perfection when we were assigned cover as a married couple in Ukraine.

There was a drunken one-night stand in Kiev, but I think of us getting together in Turkey. And then she returned to the UK, to ignominy, and the distance allowed us to begin a relationship. That we could only see each other every few weeks made it easier. We should have notified our line managers. I didn’t; I can’t imagine Joanna having that conversation.

It’s a mixed feeling when someone’s turn for the worse involves agreeing to a relationship with you. I had been worried about her, post-Turkey. Shame can drive people to all sorts of things, and it had driven her to secrecy. And I recognised, in some uneasy way, that it was bound to her desire for me. There was a current of rage and humiliation sweeping her. I understood something of that. Her reputation was destroyed but she had survived, emerged intact on the other side of ruin, and that brings a disconcerting freedom.

We’re half-dressed on the dusty ground in Turkey when Joanna’s phone buzzes, one of her contacts saying Kurds had tapped into a pipeline beside the camp. It had been going on for weeks, Turkish intelligence claiming the PKK were conducting sabotage operations. We both suspected it was the gangs running the camps. Under cover of night, they’d drill into the line, stretch a hose to a rusty tanker then drive off when they’d finished, leaving the oil flowing into the ground until the place was swimming in it – and the villagers would come out and start scooping up fuel.

‘Let’s take a look,’ she said, already dressing.