'He must have written that when he first arrived.'

'Yes, indeed,' said Dicky.

'That was before he examined my brother. Is that what you were doing all the time before he came upstairs?'

'The ambulance will be here any moment, Miss Trent. Could I trouble you to put your brother's clothes into a case or a bag? I'll see you get it back of course.' A big smile. 'He'll need his clothes in a day or two, from what I understand.'

'I'll go with him,' she said.

'I'll phone the office and ask them,' said Dicky. 'But they almost always say no. That's the trouble with trying to get things done at this time of night. None of the really senior people can be found.'

'I thought you were senior,' she said.

'Exactly!' said Dicky. That's what I mean. No one will be senior enough to countermand my decision.'

'Poor Giles,' said the woman. 'That he'd be working for a man such as you.'

'For a lot of the time, he was left on his own,' said Dicky.

Miss Trent looked up suddenly to see what he meant, but Dicky's face was as blank as hers had been. Angrily she turned to where I was sitting holding a folded newspaper and pencil. 'And you,' she said. 'What are you doing?'

'It's a crossword,' I said. 'Six letters: the clue is "Married in opera but not in Seville ". Do you get it?'

'I know nothing of opera. I hate opera, and I know nothing of Seville,' said Miss Trent. 'And if you've nothing more important than that to ask me, it's time you took yourself out of my house.'

'I've nothing more important than that to ask you, Miss Trent,' I said. 'Perhaps your brother will be able to solve it.'

Jesus, I thought, suppose Bret turned out to be a Moscow man and was trying to recruit Fiona to his cause. That would really be messy.

'It's not a crossword at all,' said Miss Trent. 'You're making up questions. That's the classified page.'

'I'm looking for another job,' I explained.

Dicky had Trent taken out to Berwick House, an eighteenth-century manor named after a natural son of James II and the sister of the Duke of Marlborough. It had been taken over by the War Office in 1940 and, like so many other good things seized temporarily by the government, it was never returned to its former owners.

The seclusion could hardly have been bettered had the place been specially built for us. Seven acres of ground with an ancient fifteen-foot-high wall that was now so overgrown with weeds and ivy that it looked more like a place that had been abandoned than one that was secret.

On the croquet lawn the Army had erected black creosoted Nissen huts, which now provided a dormitory for the armed guards, and two prefabricated structures which were sometimes used for lectures when there was a conference or a special training course in the main building. But, despite these disfigurements, Berwick House retained much of its original elegance. The moat was the most picturesque feature of the estate and it still had its bullrushes, irises and lilies. There was no sign of the underwater devices that had been added. Even the little rustic teahouse and gate lodge had been convened to guard posts with enough care to preserve their former appearance. And the infrared beams and sonic warning shields that lined the perimeter were so well hidden in the undergrowth that even the technicians who checked them did not find them of easy access.

'You've got a nerve,' said Giles Trent. 'It's kidnapping, no matter what fancy explanations Dicky gives me.'

'Your taking an overdose of sleeping tablets upset him,' I said.

'You're a sardonic bastard,' said Trent. We were in his cramped second-floor room: cream-painted walls, metal frame bed, and a print of Admiral Nelson dying at Trafalgar.

'You think I should feel sorry for you,' I said. 'And I don't feel sorry for you. That's why we are at odds.'

'You never let up, do you?'

'I'm not an interrogator,' I said cheerfully. 'And, unlike you, I never have been. You know most of our interrogation staff, Giles. You trained some of them, according to what I saw on your file. Say who you'd like assigned to you and I'll do everything I can to arrange that you get him.'

'Give me a cigarette,' said Trent. We both knew that there was no question of Trent 's being permitted anywhere near one of the interrogators. Such a confrontation would start rumours everywhere, from Curzon Street to the Kremlin. I passed him a cigarette. 'Why can't I have a couple of packets?' said Trent, who was a heavy smoker.

'Berwick House regulations forbid smoking in the bedrooms, and the doctor said it's bad for you.'

'I don't know what you wanted to keep me alive for,' said Trent in an unconvincing outburst of melancholy. He was too tail for the skimpy cotton dressing gown provided by the housekeeper's department, and he kept tugging at its collar to cover the open front of his buttonless pyjama jacket. Perhaps he remembered the interrogation training report in which he'd recommended that detainees should be made to suffer 'a loss of both dignity and comfort' while being questioned.

I said, 'They're not keeping you fit and well for the Old Bailey, if that's what you mean.'

He lit his cigarette with the matches I gave him and then hunched himself in order to take that very deep first breath that the tobacco addict craves. Only when he'd blown smoke did he say, 'You think not?'

'And have you centre stage for a publicity circus? You know too much, Giles.'

'You flatter me. I know only tidbits. When was I a party to any important planning?' I heard in his voice a note of disappointed ambition. Had that played a part in his treachery, I wondered.

'It's tidbits the government really hate, Trent. It's tidbits that are wanted for the papers and the news magazines. That's why you can never get into the Old Bailey through the crowds of reporters. They know their readers don't want to read those long reports about the Soviet economy when they could find out how someone bugged the bedroom of the Hungarian military attachés favourite mistress.'

'If not the Old Bailey, then what -?'

'I keep telling you, Giles. Just keep your friend Chlestakov happy.' I sat down on his bed. I wanted to show Trent that I was settling in for a long talk, and I knew that rumpling up his bed would irritate him. Irritation could make a man captious and indiscreet; that too was something I'd read in Trent 's training report. I said, 'He had a sense of humour, your contact from the Embassy, calling himself Chlestakov. That was the name of the impostor in Gogol's The Government Inspector. He's the man who fills his pockets with bribes, seduces the prefect's daughter, lies, cheats and swindles all the corrupt officials of the town, and then gets away scot free as the curtain falls. He does get away scot free, doesn't he? Or does he get imprisoned at the end?'

'How should I know?'

'Gogol had a sense of humour,' I persisted.

'If not the Old Bailey, what?'

'Don't shout, Giles. Well, it's obvious, isn't it? Either they will feel you've cooperated and you'll be put out to grass, and finish your days with the senior citizens of some seaside resort on the south coast – or you refuse to cooperate, and you will end up in the ambulance with the flashing lights that doesn't get to the emergency ward in time.'

'Are you threatening me?'

'Well, I hope so,' I said. 'I'm trying like hell to get some sense into your brainless head.'

'Chlestakov, or whatever his real name is, suspects nothing. But if you keep me locked up in this place you'll certainly change that. Where are we, by the way? How long was I unconscious?'

'Don't keep asking the same thing, Giles. You know I can't answer. The immediate question is: when are you going to start telling us the truth?' There was no reaction from him except to examine his cigarette to see how many more puffs he had left. 'Let's go right back to that first interrogation. I was reading it this morning…' He looked up. 'Oh, yes. I keep at it, Giles. I'm afflicted with the work ethic of the lower class. In that first interrogation you said you regularly went to the opera with your sister and Chlestakov, to pass photocopied documents to him. I was interested to notice that you used the word "treff".' I paused deliberately, wanting to see if my mention of his sister and the visits to the opera had any effect upon him. Now I watched him carefully as I prattled on. 'It's a spy word, treff. I can't say I remember ever using it myself, but I've often heard it used in films on TV. It has those romantic overtones that spying has for some people. Treff! German for meet, but also for strike or hit. And it has those irresistible military connotations: "battle", "combat", or "action". It means "line of battle" too. Did you know that, Giles?'