So I didn't tell Trent about the misery and disgrace that would be waiting for him. Instead I told him how simple it would be for me to drop this investigation, and destroy my notes and papers, in exchange for having him walking into my office the next morning and making a voluntary statement. In that way there would be no investigation; Trent would report an overture made to him from a Russian diplomat and we would brief him on how to react.

'And would the Department allow that? Would they agree to it being something that starts with a report from me?'

There was, of course, no report to change or destroy. I hadn't mentioned my conversation with Tessa to anyone at all. I nodded sagely. 'Use your imagination, Trent. What do you think the D-G would prefer? If we discover you in contact with the Russians, we've got a disaster on our hands. But if you can be described as one of our people feeding stuff to the Russians, we've got a minor triumph.'

'I suppose you're right.'

'Of course I'm right. I know how these things work.'

'You'd want me to continue my meetings with him?'

'Exactly. You'd be working for us. You'd be making a fool of him.'

Trent smiled; he liked that.

After I'd been through my piece a couple of times, Trent became friendly enough to press a couple of drinks on me and thank me for my kindness and consideration. He repeated my instructions earnestly and thankfully, and he looked up to wait for my nod of approval. For by now – in about an hour of conversation – I had established the role of father-confessor, protector and perhaps saviour too. 'That's right,' I said, this time letting the merest trace of warmth into my voice. 'You do it our way and you'll be fine. Everything will be fine. This could even mean a step up the promotion ladder for you.'

What wife, at some time or other, has not suspected her husband of infidelity? And how many husbands have not felt a pang of uncertainty at some unexplained absence, some careless remark or late arrival of his spouse? There was nothing definite in my fears. There was nothing more than confused suspicion. Fiona's embraces were as lusty as ever; she laughed at my jokes and her eyes were bright when she looked at me. Too bright, perhaps, for sometimes I thought I could detect in her that profound compassion that women show only for men who have lost them.

I'd been trying to read other people's minds for most of my life. It could be a dangerous task. Just as a physician might succumb to hypochondria, a policeman to graft, or a priest to materialism, so I knew that I studied too closely the behaviour of those close to me. Suspicion went with the job, the endemic disease of the spy. For friendships and for marriages it sometimes proved fatal.

I'd returned home very late after my visit to Giles Trent and that night I slept heavily. By seven o'clock next morning, Fiona's place alongside me in bed was empty. Balanced upon the clock-radio there was buttered toast and a cup of coffee, by now quite cold. She must have left very early.

In the kitchen I could hear the children and their young nanny. I looked in on them and took some orange juice while standing up. I tried to join in the game they were playing but they yelled derision at my efforts, for I'd not understood that all answers must be given in Red Indian dialect. I blew them kisses that they didn't acknowledge and, wrapped into my sheepskin car coat, went down into the street to spend fifteen minutes getting the car to start.

Sleet was falling as I reached the worst traffic jams, and Dicky Cruyer had parked his big Jag carelessly enough to make it a tight squeeze to get into my allotted space in the underground garage. Don't complain, Samson, you're lucky to have a space at all; Dicky – not having fully mastered the technique of steering – really needs two.

I spent half an hour on the phone asking when my new car was going to be delivered, but got no clear answer beyond the fact that delivery dates were unreliable. I looked at the clock and decided to call Fiona's extension. Her secretary said, 'Mrs Samson had an out-of-town meeting this morning.'

'Oh, yes – she mentioned it, I think,' I said.

Her secretary knew I was trying to save face; secretaries always guess right about that kind of thing. Her voice became especially friendly as if to compensate for Fiona's oversight. 'Mrs Samson said she'd be late back. But she'll phone me some time this morning for messages. She always does that. I'll tell her you called. Was there any message, Mr Samson?'

Was her secretary a party to whatever was going on, I wondered. Was it one of those affairs that women liked to discuss very seriously or was it recounted with laughter as Fiona had recounted to me some of her teenage romances? Or was Fiona the sort of delinquent wife who confided in no one? That would be her style, I decided. No one would ever own Fiona; she was fond of saying that. There was always a part of her that was kept secret from all the world.

'Can I give your wife a message, Mr Samson?' her secretary asked again.

'No,' I said. 'Just tell her I called.'

Bret Rensselaer liked to describe himself as a 'workaholic'. That this description was a tired old cliché didn't deter him from using it. He liked clichés. They were, he said, the best way to get simple ideas into the heads of idiots. But his description of himself was accurate enough; he liked work. He'd inherited a house in the Virgin Islands and a portfolio of stock that would keep him idling in the sun for the rest of his days, if that was his inclination. But he was always at his desk by 8.30 and had never been known to have a day off for sickness. A day off for other reasons was not unusual: Easter at Le Touquet, Whitsun at Deauville, the Royal Enclosure in June and the Dublin Horse Show in August were appointments marked in red pencil on Bret's year-planner.

Needless to say, Rensselaer had never served as a field agent. His only service experience was a couple of years in the US Navy in the days when his father was still hoping he'd take over the family-owned bank.

Bret had spent his life in swivel chairs, arguing with dictating machines and smiling for committees. His muscles had come from lifting barbells, and jogging around the lawn of his Thamesside mansion. And one look at him would suggest that it was a good way to get them, for Bret had grown old gracefully. His face was tanned in that very even way that comes from sun reflected off the Pulverschnee that only falls on very expensive ski resorts. His fair hair was changing almost imperceptibly to white. And the spectacles that he now required for reading were styled like those that California highway patrolmen hang in their pocket flap while writing you a ticket.

'Bad news, Bret,' I told him as soon as he could fit me into his schedule. 'Giles Trent is coming in this morning to tell us just what he's been spilling to the Russians.'

Bret didn't jump up and start doing press-ups as he was said to have done when Dicky brought him the news that his wife had walked out on him. 'Tell me more,' he said calmly.

I told him about my visit to Kar's Club and overhearing the conversation, and that I'd suggested that Trent report it all to us. I didn't say why I'd visited Kar's Club or mention anything about Tessa.

He listened to my story without interrupting me, but he got to his feet and spent a little time checking through his paperclip collection while he listened.

'Three Russians. Where were the other two?'

'Sitting in the corner, playing chess with two fingers, and saying nothing to anyone.'

'Sure they were part of it?'

'A KGB hit team,' I said. They weren't difficult to spot – cheap Moscow suits and square-toed shoes, sitting silent because their English isn't good enough for anything more than buying a cup of coffee. They were there in case the flashy one needed them. They work in threes.'