'Jesus Christ, Yasolev, I wonder you can ever sleep at night. Is there any more tea in that thing?'

He got the thermos flask and poured me some. My feet were froze and the chill was creeping all the way up my spine because the more I heard about this thing the more it looked like a massive iceberg somewhere out there on the night-black sea, drifting towards us.

'I will give you some time to think,' Yasolev said. 'Excuse me.'

He went across to pee against a tree while I stood there doing a lot of very fast thinking, holding the plastic cup of tea and taking small sips of it, burning my mouth, taking in its raw black essences with certain relish now because there was absolutely no question of letting myself get sucked into this kind of operation — it was strictly a five-star spectacular and I wasn't qualified to take it on and if Shepley wanted that operator blown out of his basement he'd have to come over here and do it himself.

'It's not on,' I told Yasolev when he came back. 'But I've left some tea for you.'

He stood very still with his small brown eyes watching me from the shadows of his brow as if he'd suddenly found me holding a gun on him.

'Tea?'

'There's some left. But I can't take this thing on. It's not my style.'

'Style?'

It was only then that I knew he'd thought I was a certainty; that Shepley had told him I wouldn't refuse. Or maybe he was just thinking like a KGB man and believed I had to obey orders, as he did.

'Look,' I told him, 'it's far too political, far too important. There's too much in the running: if you don't manage to put the skids under this operator, you're going to lose your General-Secretary and we’re going to lose Thatcher and let those snivelling socialists back in to screw up the economy again. Listen, do you mean they're planning an actual kill? Are we talking about attempted assassination?'

In a moment: 'We don't know.'

'All right, even if this operation is aimed simply at getting Gorbachev out of office, then you've not only lost him as a leader but in my opinion we've all lost the biggest chance of genuine world peace we've had for the last fifty years, if the Americans can find a president like Nixon who can really get down to brass tacks at a summit meeting. So this is something I'm not even qualified to touch. Sorry.'

I thought he'd never answer.

'It frightens you.'

'How did you guess?'

'Your Mr Shepili believes you are the best agent for this.'

'He's not infallible.'

'You'd say that, to his face?'

KGB thinking, yes.

'Of course. But it's not only the size of this thing, Yasolev. You want me to work with your people in close support. I couldn't do that.'

'Why not?'

'It'd hamper my movements. It'd mean tagging, and not always in good light. I wouldn't necessarily know who the tags were — yours or the opposition's. That's dangerous, could be fatal.'

I finished my tea and put the cup down onto the rough linen cloth and looked at my watch.

'But of course we would have to put tags on you — ' suddenly animated, his thick square hands coming out of his coat pockets and chopping at the air '- how else could we possibly work? We — '

'I work alone, unless I call people in. You're — '

'Mr Shepili would allow that?'

'Of course. He — '

'But you would be working with us, the KGB.'

'I know that.'

'Perhaps — ' on a sudden thought '- it's this that frightens you?'

'Perhaps.'

'Without reason.' Hands chopping the air again.

'Possibly.'

'Then I do not understand you.'

'And that's the problem,' I said. 'We can't even agree on basic principles, so what d'you think would happen if we tried to get through an entire mission together? Christ, it'd be like a dog fight.'

He didn't leave it at that; I didn't expect him to. We started walking, to keep our feet warm, in and out of the trees and down the slope and up again while Yasolev made his pitch and I countered when I had to, not wanting to leave him with nothing in his hands, because they'd made the approach, the KGB, or his department of the KGB, and we didn't have any reason to turn them down without grace, without respect.

The normal trappings of a mission on foreign soil weren't applicable: there'd be no need for courier lines or contacts or drops or a safe-house because Yasolev's network would contain all those things; I'd be noted by the East German police and secret services as an agent to be left alone but given assistance if I asked for it, and that would be totally acceptable; but it would mean working the mission under the concerted scrutiny of those same organisations, a fly in a spotlight, and that was enough to chill the nerves of any agent even before the action got under way.

If I took this thing on I'd be one small alien cog enmeshed in the machinery of the most powerful and most ruthless intelligence organisation in the world, and it could reverse its direction at any given stage of the mission and grind me into pulp if it suited its purposes. Let's face it: that shot we'd heard earlier, deep in the trees, had triggered the image of a man going down because the last time I'd been fired on it had been by this man's agents, less than a year ago.

It was two hours before he saw I meant it, and then he walked off along the top of the slope to isolate himself and do some thinking, and when he came back his face was expressionless and he just said: 'Very well.'

Not quite that, exactly — the words he'd used were Horocho… Tak e buit. With a more fatalistic tone: So be it.

'Sorry,' I said. 'It could've been a whole lot of fun.'

I screwed the top back on the thermos flask and he pulled out his radio and told them he was escorting me to the checkpoint and we left the remains of our little picnic on the tree-stump and went down the slope to the road, and in the car I said, 'But listen, Yasolev, you'll have to find someone to do this for you. No one in their senses wants anything to happen to your man Gorbachev. It's just that I can't work like that, you understand?'

He ignored that, and sank into a brooding silence all the way to the checkpoint. His car had followed us up and he got out of mine and told the border guards the score and then leaned in to look at me with his eyes sunk deep under his brows and his hands still in his coat pockets and said with a tight mouth: 'You undervalue your talent, you know, and that is very disappointing for us. For all of us.'

He slammed the door shut and stood away and we got rolling and when we were back in the West I leaned forward.

'British Embassy, on Unter den Linden.'

By the time we got there I was starting to sweat and I showed my identity in the hall and took the stairs two at a time and went into the signals room without knocking and asked the man at the desk to put me on the scrambler to London through the Government Communications HQ in Cheltenham. Time hadn't meant anything when I'd been talking to Yasolev in the woods but I was in a hurry now because I'd had a chance to do some thinking on the drive to the checkpoint and the whole thing had come spinning round full-circle in my mind and I knew what I had to do.

'Anyone specific, sir?'

'What? No, main signals board. No, cancel that. Ask for Bureau One. Are you already on the scrambler?'

'Yes. I'm trying them now.'

He pressed three more keys and I stood waiting with a cold skin and the heart-rate elevated: I could feel it under the rib cage. The thing was, the whole thing was that I'd been looking at this project as if it were just another mission and it wasn't, it was not, and I suppose it had taken a bit of time to sink in. Either that or the subconscious had already made up its mind that we should keep well clear, and it had steered my conscious decision-making. Put it in English: I'd been shit-scared. All right, it was indeed the size of the thing that had rocked me back and it was certainly the idea of working with the KGB that had sent the nerves running for cover but I'd overlooked the obvious, the absolute.