It had happened before. That was the trouble with agents: you sent them to the West and sometimes they simply stayed there and thumbed their noses at you. 'He has no relatives here, does he?'

'He'll work for us, Colonel Moskvin. He is the sort of man who loves a good secret.'

Now that she had equated Moskvin with those Oxford hearties, she found herself remembering her college days. How she'd hated it: the good times she'd had were now forgotten. She recalled the men she'd known, and those long evenings in town, watching boorish undergraduates drinking too much and making fools of themselves. Keen always to make the women students feel like inferior beings. Boys with uncertain sexual preferences, truly happy only in male society, arms interlinked, singing together very loudly and staggering away to piss against the wall.

She went to Babelsberg in the southwest of Berlin to get Werner Volkmann. It was not very far as the crow flies, but crows flew across the Western sector of the city while good communists had to journey round its perimeter. This was just outside the city limits and not a part of Berlin: it was Potsdam in the DDK, and so the British and American 'protecting powers' did not have the legal right to come poking around here. Volkmann was in the Ausland Block, some buildings that had started out as administration offices of the famous UFA film studios.

Behind the empty film library building, and the workshops, there was an old backlot where the remains of an eighteenth-century village street built originally for the wartime film Münchhausen could be seen. 'That was Marlene Dietrich's dressing room,' said the elderly policeman who took her to the interview room. He indicated a store room with a padlock on the door.

'Yes,' said Fiona. The same policeman had said the same thing to her the last time she was here. The interview room had a barred window through which she could see the cobbled yard where she'd parked her car.

'Shall I bring the prisoner?'

'Bring him.'

Werner Volkmann looked bewildered when he was brought in. Hands cuffed behind his back, he was wearing a scuffed leather overcoat upon which there were streaks of white paint. His hair was uncombed and he was unshaven.

'Do you recognize me, Werner?'

'Of course I recognize you, Frau Samson.' He was angry and sullen.

'I'm taking you to my office in Karl Liebknecht Strasse. Do I need an armed police officer to keep you under observation?'

'I'm not going to run away, if that's what you mean.'

'Have they told you what you are charged with?'

'I want a lawyer, a lawyer from the West.'

'That's a silly thing to ask, Werner.'

'Why is it?'

It was extraordinary that Werner, a German who came here regularly, still did not understand. Well, perhaps the best way to start was to make him realize what he was up against. This is the DDR, Werner, and it is 1984. We have a socialist system. The people…'

'The government.'

'The people,' she repeated, 'don't just control the politics and the economy, they control the courts, the lawyers and the judges. They control the newspapers, the youth leagues and the women's associations and chess clubs and anglers' societies. The privilege of writing books, collecting stamps, singing at the opera or working at a lathe – in fact the right to work anywhere – can be withdrawn at any time.'

'So don't ask for a lawyer from the West.'

'So don't ask for a lawyer from the West,' agreed Fiona. 'You'll have to sit in the back of the car. I can't remove the handcuffs. I can't even carry the key. It's a regulation.'

'Can I wash and shave?'

'At the other end. Do you have any personal possessions here?'

Werner shrugged and didn't answer.

'Let's go.'

'Why you?' asked Werner as they were walking across the cobbled courtyard to her Wartburg car.

'Machtpolitik,' said Fiona. It meant negotiations under the threat of violence and was a uniquely German word.

None of the long-dead city officials who drew the outlandish shape of the old boundaries could have guessed that one day Berlin would be thus circumscribed and divided. Jutting southwards, Lichtenrade – where the S-Bahn line is chopped off to become a terminal, and where Mozart, Beethoven and Brahms are streets that end at the Wall – provides an obstacle around which Fiona had to drive to get back to her office in central Berlin.

The normal route back kept to the main road through Mahlow, but Fiona went on to back streets that might have saved her a few minutes in travelling time, except that when she got beyond Mahlow she turned off to a sleepy little neighbourhood beyond Ziethen. Here the pre-war housing of a 'Gartenstadt' had spilled over the Wall into the Democratic Republic. Bordered on three sides by the West, these wide tree-lined roads were empty, and the neighbourhood quiet.

'Werner,' said Fiona as she stopped the car under the trees of a small urban park and switched off the engine. She turned to look back at him. 'You are just a card in a poker game. You know that, I'm sure.'

'What happens to a card in a poker game?' asked Werner.

'At the end of the game you are shuffled and put away for another day.'

'Does it hurt?'

'Within a few days you'll be back in the West. I guarantee it.' A car came very slowly up the street. It passed them and, when it was about a hundred yards ahead, stopped. Werner said nothing and neither did Fiona. The car turned as if to do a U-turn but stopped halfway and then reversed. Finally it went past them again and turned to follow the sign that pointed to Selchow. 'It was a car from a driving school,' said Fiona.

'Why are you telling me this?' said Werner. The car had made him jumpy.

'I want you to take a message.'

'A written message?'

Good old Werner. So he wasn't so simple. 'No, Werner, a verbal message.'

'To Bernard?'

'No. In fact you'd have to promise that Bernard will know nothing of it.'

'What sort of game is this?'

'You come through regularly, Werner. You could be the perfect go-between.'

'Are you asking me to work for Moscow?'

'No I'm not.'

'I see.' Werner sat back, uncomfortable with his hands cuffed behind him. Having thought about it he smiled at her. 'But how can I be sure?' It was a worried smile.

'I can't do anything about the handcuffs, Werner. It is not permitted to have keys together with prisoners in transit.'

'How can I be sure of you?' he said again.

'I want you to go and talk with Sir Henry Clevemore. Would that satisfy your doubts?'

'I don't know him. I've never even seen him.'

'At his home, not in the office. I'll give you a private phone number. You'll leave a message on the answering machine.'

'I'm not sure.'

'Jesus Christ, Werner! Pull yourself together and decide!' she yelled. She closed her eyes. She had lost control of herself. The driving school car had done it.

Werner looked at her with amazement and suddenly understood the panic she had shown. 'Why me? Why now? What about your regular contact?'

'I have no regular contact. I have been finding my way around, using dumps. London would probably have sent someone in a month or so. But this is a perfect opportunity. I will enrol you as a Stasi agent. You'll report to me personally and each time you do I will give you the material to take back.'

'That would work,' said Werner, thinking about it. 'Would Sir Henry arrange material for me to bring?'

'All my reports must be committed to memory,' said Fiona. She had done it now: she had put herself at Werner's mercy. It would be all right. Later she would get Werner to tell her about her husband and her children but not now. One thing at a time.

Now he was beginning to believe. His face lit up and his eyes widened. He was to participate in something really tremendous. 'What a coup!' he said softly and with ardent admiration. In that moment he had become her devoted slave.