'We copied it from a picture of Mick Jagger,' Billy told me. 'And then we drew your glasses on afterwards. I did the outline and Sally filled in the colours.'

'And that's a pyramid in Mexico,' said Sally. 'We copied it from the encyclopedia.'

'It's beautiful,' I said. 'Can I keep it?'

'No,' said Billy. 'Sally wants to take it to school.'

I went into the little room where I keep my typewriter, books and unpaid bills. I looked up 'fink' in my dictionary of American slang.

fink n. 1 A company spy, secret informer or strike breaker.

(Orig. Pink, contraction of Pinkerton man.)

I wondered how Pavel Moskvin fitted to that definition and what else Paul Biedermann had been about to tell me about it.

I knew what to expect. That was why I lingered over breakfast, spent a little extra time with the children and chose a dark suit and sober tie. Bret Rensselaer chose to see me in the number 3 conference room. It was a small top-floor room that was normally used when the top brass wanted to have a cozy chat far away from the noise of the typewriters, the smell of copying machines and the sight of the workers drinking tea from cups without saucers.

There was a coffin-shaped table there and Bret was in the chairman's seat at the head of it. I was at the other end. The rest of them – Dicky Cruyer and his friend Henry Tiptree, together with Frank Harrington and a man named Morgan, who was general factotum and hatchet man for the D-G – were placed so that they were subject to Bret's authority. Quite apart from anything that might happen to me, Bret was going to stage-manage things to get maximum credit and importance. Bret was a 'department head' looking for a department, and there was no more dangerous animal than that stalking through the corridors of Whitehall. He was wearing a black worsted suit – only a man as trim as Bret could have chosen a fabric that would show every spot of dust and hair – and a white shirt with stiff collar and the old-fashioned doubled-back cuffs that require cufflinks. Bret's cuff-links were large and made from antique gold coins, and his blue-and-white tie was of a pattern sold only to Concorde passengers.

'I've listened,' said Bret. 'You can't say I haven't listened. I'm not sure I'm able to understand much of it but I've listened to you.' He looked at his watch and noted the time in the notebook in front of him. Bret had gone to great pains to point out to me how informal it all was; no stenographer, no recording and no signed statements. But this way was better for Bret, for there would be no record of what had been said except what Bret wrote down. 'I've got a hell of a lot of questions still to ask you,' he said. I recognized the fact that Bret was ready for any sort of showdown; 'loaded for bear' was Bret's elegant phrase for it.

I was trying to give up smoking but I reached for the silver-plated cigarette box that was a permanent feature of top-floor conference rooms, and helped myself. No one else wanted a cigarette. They didn't want to be associated with me by thought, theory or action. I had the feeling that if I'd declared abstinence they'd all have rushed out to get drunk. I lit up and smiled and told Bret that I'd be glad to do things any way he wanted.

There were no other smiles. Frank Harrington was fiddling with his gold wrist-watch, pushing a button to see what time it was in Timbuctoo. Henry Tiptree, having written something that was too private to say, was now showing it to Morgan. Bret seemed to have hidden away the little notepads and pencils that were always put at each place on the table. That had effectively prevented note-taking except for the freckle-faced Tiptree, who'd brought his own notepad. Dicky Cruyer was wearing his blue-denim outfit and a sea-island cotton sports shirt open enough to reveal a glimpse of gold chain. Now it was obvious that Dicky had known all along that Henry Tiptree was an Internal Security officer. I'd never forgive him for not warning me back in Mexico City when Tiptree first came sniffing around.

Bret Rensselaer took off the big, wire-frame, speed-cop-style glasses that he required for reading and said, 'Suppose I suggested that you were determined that Stinnes would never be enrolled? Suppose I suggested that everything you've done from the time you went to Mexico City – and maybe before that, even – has been done to ensure that Stinnes stays loyal to the KGB?' He raised a hand in the air and waved it around as though he was trying to get someone to bid for it. 'This is just a hypothesis, you understand.'

I took my time answering. 'You mean I threatened him? Are you "suggesting" that I told him that I worked for the KGB and that I'd make sure that any attempt to defect would end in disaster for him?'

'Oh, no. You'd be far too clever for a crude approach like that. If it was you, you wouldn't tell Stinnes anything about your job with the KGB. You'd just handle the whole thing in an incompetent fumbling way that would ensure that Stinnes got scared. You'd make sure he was too damned jumpy to make any move at all.'

I said, 'Is that the way you think it was handled, Bret? In an incompetent fumbling way?' No hypothesis now, I noticed. The incompetence was neatly folded in.

Mexico City had been Dicky's operation and Dicky was quick to see that Bret was out to sink him. 'I don't think you have all the necessary information yet,' Dicky told Bret. Dicky wasn't going to be sunk, even if it meant keeping me afloat.

'We were taking it slowly, Bret,' I said. 'The brief implied that London wanted Stinnes gung-ho, and ready to talk. We didn't want to push hard. And you said London Debriefing Centre wouldn't want to find themselves dragging every word out of him. Frank will remember that.'

Bret realized that he could get caught in the fallout. Defensively he said, 'I didn't say that. What the hell would I know about what the Debriefing Centre want?'

Dicky leaned forward to see Bret and said, 'Words to that effect, Bret. You definitely said that Bernard was to use his own judgement. He decided to do things slowly.'

'Maybe I did,' said Bret and, having pacified Dicky, turned the heat back on to me. 'But how slow is slow? We don't want Stinnes to die of old age while you're enrolling him. We want to speed things up a little.'

I said, 'You wanted to speed things up. So you applied the magic speed-up solution, didn't you? You offered Stinnes a quarter of a million dollars to help him make up his mind. And you did it without even informing me, despite the fact that I am the enroller. I'm going to make an official objection to that piece of clumsy meddling.' I turned to the D-G's personal assistant and said, 'Have you got that, Morgan? I object to that interference with my operation.'

Morgan was a white-faced Welshman whose only qualifications for being in the department were an honours degree in biology and an uncle in the Foreign Office. He looked at me as if I were an insect floating in his drink. His expression didn't change and he didn't answer. On the day I leave the department I'm going to punch Morgan in the nose. It is a celebration I've been promising myself for a long time.

Bret continued hurriedly, as if to cover up for the way I'd made a fool of myself. 'We were in a hurry to debrief Stinnes for reasons that must be all too clear to you.'

'To question him about Fiona's defection?' I said. 'Would you push that ashtray down the table, please?'

'It wasn't a defection, buddy. To defect means to leave without permission. Your wife was a KGB agent passing secret information to Moscow.' He slid the heavy glass ashtray along the polished table with that violent aplomb with which bartenders shove bourbon bottles in cowboy films.