I drank some more coffee. I began to have the feeling that Zena didn't intend to leave us alone to talk about the things we had to talk about. I kept the small talk going. 'It killed old Biedermann,' I said. 'He had nothing to live for after the yard closed and the company was being run from New York. Do you remember how he used to sit in Leuschner's cafe all day, talking about old times to anyone who would listen, even to us kids?'

'It's the way things are now,' said Werner. 'Companies are run by computers. Profit margins are sliced thin. And no manager dare raise his eyes from his accounts long enough to learn the names of his staff. It's the price we pay for progress.'

Zena picked up the ashtray containing the broken cup and saucer. I could tell that Werner had broken it by the way she averted her eyes from him. She took the coffee-pot too and went to the kitchen. I said, 'Dicky saw Frank Harrington in LA. Apparently London have decided to try enrolling Erich Stinnes.' I had tried to make it unhurried but it came out in a rush.

'Enrolling him?' I was interested to see that Werner was as dismayed and surprised as I had been. 'Is there any background?'

'You mean, have there been discussions with Stinnes before. I was wondering the same thing myself but from what I got out of Dicky I think the idea is to go in cold.'

Werner leaned his considerable weight back in the armchair and blew through his pursed lips. 'Who's going to try that?'

'Dicky wants you to try,' I said. I drank some of my strong coffee and tried to sound very casual. I could see that Werner was torn between indignation and delight. Werner desperately wanted to become a regular departmental employee again. But he knew that being chosen for this job was no tribute to his skills; he was simply the man closest to Stinnes. 'It's a great opportunity,' said Werner resentfully, 'a great opportunity for failure. So Frank Harrington, and all those people who've been slandering me all these years, can have a new excuse and start slandering me all over again.'

'They must know the chances are slim,' I said. 'But if Stinnes went for it, you'd be the talk of the town, Werner.'

Werner gave me a wry smile. 'You mean both East and West sides of it?'

'What are you talking about?' said Zena, returning with the coffee. 'Is this something to do with Erich Stinnes?'

Werner glanced at me. He knew I didn't want to discuss it in front of Zena. 'If I'm going to try, Zena will have to know, Bernie,' he said apologetically. I nodded. The reality was that Werner told her everything I told him, so she might as well hear it from me.

Zena poured more coffee for us and offered us a selection of Spritzgebäck, little German biscuits that Werner liked. 'It is about Stinnes, isn't it?' she said as she picked up her own coffee – she drank it strong and black – and sat down. Even in this severe dress she looked very beautiful; her big eyes, very white teeth and the high cheekbones in that lightly tanned face made her look like the work of some Aztec goldsmith.

'London want to enrol him,' said Werner.

'Recruit him to work for London, do you mean?' said Zena.

'You recruit ordinary people to become spies,' Werner explained patiently. 'But an enemy security officer, especially one who might help you break his own networks, is "enrolled".'

'It's the same sort of thing,' said Zena brightly.

'It's very different,' said Werner. 'When you recruit someone, and start them spying, you paint romantic pictures for them. You show them the glamour and make them feel courageous and important. But the agent you enrol knows all the answers already. Enrolment is tricky. You are telling lies to highly skilled liars. They're cynical and demanding. It's easy to start it off but it usually goes sour some way along the line and everyone ends up mad at everyone else.'

'You make it sound like getting a divorce,' said Zena.

'It's a bit like that,' I said. 'But it can get more violent.'

'More violent than a divorce?' Zena fluttered her eyelashes. 'You're only going to offer Erich Stinnes a chance to defect to the West. 'Can't he do that any time he wants? He's in Mexico. Why go back to Russia if he doesn't want to?' There was something deliciously feminine about Zena and her view of the world.

'It's not as easy as that,' said Werner. 'Not many countries will allow East European nationals to defect. Seamen who jump ship, passengers or Aeroflot crew who leave their planes at refuelling stops, or Soviet delegates who walk into foreign police stations and ask for asylum find it's not so easy. Even right-wing governments send them right back to Russia to face the music.' He bit into a biscuit. 'Good Spritzgebäck, darling,' he said.

'I couldn't get hazelnuts but I tried this other sort; with honey. They're not bad, are they? Why won't they let them defect? They send them back to Russia? That's disgusting,' said Zena.

'Encouraging defectors upsets the Russians for one thing,' said Werner. 'If Stinnes said he wanted to stay in Mexico, the Soviet ambassador would go running along to the Foreign Secretary and start pressurizing the Mexican authorities to hand him back.'

'In which case doesn't Stinnes just say go to hell?' said Zena.

'The ambassador then says that Stinnes has stolen the cash box or that he's wanted to face criminal charges in Moscow. The Mexicans then find themselves accused of harbouring a criminal. And don't forget that someone has to pay the defector a salary or find him a job.' Werner reached for another biscuit.

'This is Mexico,' said Zena. 'What do they care about the Russians?'

Werner was fully occupied with the biscuits. I said, The Russians have a lot of clout in this part of the world, Mrs Volkmann. They can stir up trouble by getting neighbouring countries to apply pressure. Cuba will always oblige, since its economy depends totally on Soviet money. They can apply economic sanctions. They can influence United Nations committees and all the rigmarole of Unesco and so on. And all of these countries have to contend with a domestic Communist Party organization ready to do whatever the Russians want done. Governments don't offend the Soviet Union without very good reason. Providing asylum for a defector is seldom reason enough.'

'There are still plenty of defectors, though,' persisted Zena.

'Yes,' I said. 'Many defectors are sponsored by the USA, the way that famous musicians or performers are, because of the bad publicity their escapes make for the communist system. And they can earn their own living easily enough. The remainder have to bring something worthwhile with them as the price of entry.'

'Secrets?'

That depends on what you call secrets. Usually a country provides asylum to someone bringing information about the way the Soviets have been spying on the host country. For that sort of information a government is usually prepared to withstand Russian pressures.'

'And for that reason,' said Werner, 'most of the decent Russians can't defect and the KGB bastards can. Put all the defectors together and you'd have a ballet company and orchestra, some sports stars and a vast army of secret policemen.'

Zena looked at me with her big grey eyes and said archly, 'But if you two are right about Erich Stinnes, he's a KGB man. So he could provide some secrets about spying on Mexico. So he would be allowed to stay here without your help.'

'Would you like to live in Mexico for the remainder of your life, Mrs Volkmann?' I said.

She paused for a moment as if thinking the idea over. 'Perhaps not,' she admitted.

'No, a man such as Stinnes would want a British passport.'

'Or a US passport?' said Zena.

'American citizenship provides no right to travel abroad. A British passport identifies a British subject, and they have the right to leave the country any time they wish. Stinnes will give us quite a list of requirements if he decides to defect. He'd need a lot of paperwork so that he has a completely new identity. I mean an identity that is recorded in such a way that it will withstand investigation.'