His vigorous puffing had already burned the cigarette down and now he was nursing it, holding it to his lips and trying to make it last. 'I never thought about it.'

'That's probably why Chlestakov used it on you. It made you both feel more daring, more rakish, more like men who change history. I once asked one of the KGB people why they gave their agents all those gadgets of the sort they gave you. The camera that looks like a cigarette lighter, the radio transmitter disguised like a video recorder and the one-time pads and all that. Chlestakov never asked you to use any of that junk – the KGB almost never do. Why would they bother, when all they have to do in a free society is have one of their hoodlums take a cab across town and have a chat or spend a couple of minutes in a photocopy shop? And this KGB man told me that it gave their agents confidence. Is that what it did for you, Giles? Did it make you feel more sure of yourself to have all that paraphernalia? It was fatal, of course. When we found all that stuff under the floorboards, you were sunk. Silly place, under the floorboards. Floorboards and attics – always the first place the searchers look. Was that Chlestakov's suggestion?'

'As a matter of fact, it was,' said Trent. He got to his feet and, pulling the belt of his dressing gown tighter, went to the door. He opened it and looked along the corridor. When he came back again, he muttered something about wanting a cup of tea. He said he thought he'd heard the nurse coming, but I knew I had him worried.

'To get back to the point, Giles. You said that you got opera tickets for Chlestakov and your sister, so that the three of you would look' – I paused – 'less conspicuous. That was a funny thing to say, Giles. I was thinking about that last night when I couldn't get to sleep. Less conspicuous than what, I thought. Less conspicuous than two men? It didn't make sense to me. Why would you take your sister along to the opera when you wanted to keep your meetings with Chlestakov as secret as possible? So I got up and started reading your transcript again. I found your descriptions of those visits to the opera. You quote your sister as saying that 'Mr Chlestakov was a pleasant man, considering he was a Russian.' I suppose you said that to emphasize the fact that your sister had no particular liking for Russians.'

'That's right,' said Trent.

'Or even that she was prejudiced against Russians.'

'Yes.'

'Whatever your sister's feelings about Chlestakov and his comrades, it certainly seems from your transcript that she was aware of his name and his nationality. Am I right?'

'Yes.' Trent had stopped pacing now. He stood by the little electric fire built into the fireplace and rubbed his hands together nervously. 'She loved the opera. Having her with, us provided a reason for the meeting.'

'Your sister hasn't been entirely honest with you, Giles,' I said. 'Last night I invented a question that even the worst-informed opera buff in the world would have been able to answer. Your sister told me she didn't like opera. She said it vociferously. She said it as if she had some special reason for hating it.'

'I don't know what you're getting at.'

'Are you cold, Giles? You're shivering.'

'I'm all right.'

'We know the way it really happened, don't we, Giles? They got to you by means of your sister. Did Chlestakov, a nice gentleman of about the right age, go into that little wool shop your sister owns and ask help in choosing wool? For his mother? For his sister? For his daughter? Not for his wife – what had happened to her? Was he a widower? That's what they usually say. And then when the relationship had flowered – they're never in a hurry, the KGB, and I do admire that; we are always in a rush and the Americans even more so – eventually your sister suggests that you join their outings. And you say yes.'

'You make it sound so carefully planned.' He was angry, but his anger was not directed at me. It was not directed at anyone. It exploded with a plop, like a bullet thrown onto the fire.

'And you still want to believe it wasn't, eh? Well, I don't blame you. It must make a man angry to find he's performed his prescribed role in a play written in Moscow.'

'She nursed my father for ten years. She turned down good proposals of marriage. Was I supposed to crush her little chance of happiness?'

I shook my head in disbelief. 'Are you telling me that you thought it was all true? You thought Prince Charming had walked through the door of the wool shop, and your sister's foot just happened to fit the glass slipper? You thought it might be just a coincidence that he worked for the KGB and you worked for the Secret Intelligence Service?'

'He worked for the Soviet Trade Delegation,' growled Trent.

'Don't make jokes like that, Giles,' I said. 'You'll have me fall over laughing.'

'I wanted to believe it.'

'I know,' I said. 'Just like me and Santa Claus, but one day you have to ask yourself how he gets those bloody reindeer down the chimney.'

'What's the difference whether I went to the opera with them, or she came to the opera with us?'

'Now that's a question I can answer,' I said. 'The D-G wouldn't want to put you into the dock, for reasons we've already discussed. But there would be no such inhibitions about putting your sister there.'

'My sister?'

'With you as unnamed witness. You know how these things are done. You've read newspaper accounts of spy trials. In your circumstances, I'd have thought you'd read them with great care and attention.'

'She has nothing to do with this business.'

'You'd be silly to imagine that would be enough to keep her out of prison,' I said.

'You swine!'

'Think it over,' I said.

'I'll kill myself,' he said desperately. 'I'll make a good job of it next time.'

'And leave your sister to face the music alone? I don't think you will,' I said.

He looked so miserable that I gave him a couple of cigarettes and promised to have his clothes sent up to him. 'Have your regular medical check and take your tablets or whatever it is the nurse wants. Have lunch and then we'll have a stroll in the garden.'

'Garden? It's more like a jungle.'

'Be ready at two o'clock.'

'Be ready for what?'

'Be ready to come clean on your pal Chlestakov, and straighten out a few of the inconsistencies I've come across in your transcript.'

'What inconsistencies?'

'That would be telling, wouldn't it?'

There were gaps of blue sky, but the clouds were darkening to nimbostratus and there was rain in the air. Trent wore a short car jacket with a fur collar, which he turned up round his ears. On his head was a rather smart peaked cap that had come from an expensive hatter.

He seemed ill at ease in the country, and smoked another cigarette instead of breathing the fresh air. 'When will they let me out of here?' he asked. Having disposed of his cigarette, he picked up a twig, broke it into pieces and tossed them into the stagnant-looking moat.

'You go home tomorrow.'

'Is there someone who will cash a cheque for me?'

'See the cashier.' We walked alongside the moat until we came to a small wooden bridge and crossed it to where the shrubbery became neglected woodland. 'There was a postcard from Chlestakov,' I told him.

'At my home?'

'Where would you expect it to arrive?'

'He wants a meeting?'

'It says someone named Geof is having a fishing weekend. He caught four big fish of unspecified type and hopes to be back at work by two p.m. on the 16th of this month. I trust that means something to you.'

'It means nothing to you then?'

'It means only that the Moscow spy machine creaks along using the same antiquated ideas that have proved cumbersome for two decades or more.'

'It seems to work,' said Trent defiantly.