Someone appeared at the door: a couple of kids aged thirteen or fourteen apparently attracted by the noise. They stopped at what they saw. ‘Piss off,’ the older Sec barked at them. They took his order and hurried away.

Tibbot was pushing himself on to his side.

‘Are you all right?’ I asked, afraid to help him up.

‘Yeah.’ But he wasn’t breathing well and I hoped he was only winded.

The senior Sec took a notebook from his hip pocket, turned his back on us and marched over to a bashed-about call box in the corner of the room. He flipped through his book until he found what he was looking for, called a number and mumbled into the telephone. Tibbot pulled his jacket off and threw it angrily to the side. We all waited, freezing in the dank room as the Sec made his call.

A train, an express hooting its speed, came through in the opposite direction to ours. Distant road traffic provided a distorted chaos of noise. We waited, still. After a minute, the older man came back. ‘The car is not stolen. There hasn’t been any crime. It doesn’t concern you any more, so you can go back to nicking pickpockets or whatever you normally do. Your inspector has been informed. I doubt he’s over the moon.’ Another train was pulling in on its way to London. ‘You’re getting on that one.’

‘Are we?’ Tibbot spat. I could hear the ice in his words.

‘Yes. You are.’

Tibbot raised his head. He waited a moment before speaking. ‘I’ve been in this game longer than you have, son,’ he said. ‘You learn some things.’ He stood up stiffly, plucked his dirt-streaked jacket from the ground and walked towards the train.

As the train pulled into Blackfriars, I was reminded of the moment I had met Nick on the platform at Waterloo Station. Even after what had happened, the memory could still make me smile. But I had to come to terms with the fact that he wasn’t coming back to me – what Rachel had said left little room for doubt – and if I ever saw him alive again it would be in a military court, where I would be giving evidence against him. I wouldn’t have any choice about that. I would look at him across the room and it would split my heart, but if they ordered me to declare that I had witnessed him passing messages to American spies or that he had tried to recruit me to the cause, I would. He wouldn’t blame me; he would understand.

‘Well, thank you,’ I told Tibbot as we stood on the platform. I knew that the moment he turned his back, the tears would flood out and I wanted to be alone with that grief.

‘I didn’t help much in the end.’

‘No, but, well, I would have been much worse on my own.’