Tilney watched me, not looking away much, a thin man with glasses and ginger hair and pale freckled hands, straight out of some redbrick university, you would have said, the science department We'd been in this bloody place for years, he and I, and we got on well enough, even when the Signals room was running hot.

'He asked you to follow him up. Had he tried to phone you before, at your flat or anywhere?'

'I don't know,' I said.

'I mean, how important was it to him? Did he sound worried?'

'He just said it off-hand.'

'But he must have been expecting some sort of attack? To have asked you to follow him up?'

I didn't want to talk about it, but it was no use telling him that. 'Not necessarily attack. Perhaps surveillance. Wanted to know if there were any ticks on his tail.'

Tilney looked at me. 'McCane was a top shadow. He didn't need anyone to help him find out if he was being surveilled. If he -'

'All right, then he was expecting someone to try killing him, if you like, I don't know, how can I?'

Tilney looked away. He knew the score now: McCane had thought someone was liable to have a go at him and he'd asked me to cover his rear and I'd done that but I hadn't done it well enough and he'd ended up in a burning car and I was trying to think of some way of ever getting any sleep again.

'What actually happened?' Tilney asked quietly.

'He was about a hundred yards in front of me, most of the time, and just this side of Redhill when we were on a straight stretch another car came up from behind me and went past like a bat out of hell and cut across McCane's bows and he swerved and went into the trees and the tank burst and the whole thing went up.'