'It has been known,' I said, although I was damned if I could recall any examples of such sloppy tactics by the plodding but thorough bureaucrats of the KGB.

'How much?' said Zena. And, when Dicky looked at her and raised his eyebrows, she said, 'How much are you going to give us for reporting Stinnes? Werner said you want him badly. Werner said he was very important.'

'Steady on,' said Dicky. 'We don't have him yet. We haven't even positively identified him.'

'Erich Stinnes,' said Zena as if repeating a prepared lesson. 'Fortyish, thinning hair, cheap specs, smokes like a chimney. Berlin accent.'

'Beard?'

'No beard,' said Zena. Hastily she added, 'He must have shaved it off.' She did not readily abandon her claims.

'So you've spoken with him' I said.

'He's there every Friday,' said Werner. 'He's a regular. He works at the Soviet Embassy, he told Zena that. He says he's just a driver.'

'They're always drivers,' I said. 'That's how they account for their nice big cars and going wherever they want to go.' I poured myself some more of Werner's fruit punch. There was not much of it left, and the bottom of the jug was a tangle of greenery and soggy bits of lemon. 'Did he talk about books or American films, Zena?'

She swung her legs out of the reclining chair with a display of tanned thigh. I saw the look in Dicky Cruyer's face as she smoothed her dress. She had that sexy appeal that goes with youth and health and boundless energy. And now she knew she had the right Stinnes her pearly grey eyes sparkled. 'That's right. He loves old Hollywood musicals and English detective stories…'

'Then that's him,' I said, without much enthusiasm. Secretly I'd hoped it would all come to nothing and I'd be able to go straight back to London and my home and my children. 'Yes, that's "Lenin"; that's the one who took me down to Checkpoint Charlie when they released me.'

'What will happen now?' said Zena. She was short; she only came up to Dicky's shoulder. Some say short people are aggressive to compensate for their small stature, but look at Zena Volkmann and you might start thinking that aggressive people are made short lest they take over the whole world. Either way Zena was short and the aggression inside her was always bubbling along the edges of the pan like milk before it boils over. 'What will you do about him?'

'Don't ask,' Werner told her.

But Dicky answered her, 'We want to talk to him, Mrs Volkmann. No rough stuff, if that's what you are afraid of.'

I swallowed my fruit punch and got a mouthful of tiny pieces of ice and some lemon pips.

Zena smiled. She wasn't frightened of any rough stuff; she was frightened of not getting the money for arranging it. She stood up and twisted her shoulders, slowly stretching her arms above her head one after the other in a lazy display of overt sexuality. 'Do you want my help?' she said.

Dicky didn't answer directly. He looked from Zena to Werner and back again and said, 'Stinnes is a KGB major. That's too low a rank for the computer to offer much on him. Most of what we know about him came from Bernard, who was interrogated by him.' A glance at me to stress the unreliability of uncorroborated intelligence from any source. 'But he's senior staff in Berlin. So what is he doing in Mexico? Must be a Russian national. What's his game? What's he doing in this German club of yours?'

Zena laughed. 'You think he should have joined Perovsky's?' She laughed again.

Werner said, 'Zena knows this town very well, Dicky. She has aunts and uncles, cousins and a nephew here. She lived here for six months when she first left school.'

'Where, what, how or why is Perovsky's?' said Dicky. He was German Stations Controller. He didn't like being laughed at, and I could see he was taking a little time getting used to Werner calling him Dicky.

'Zena is joking,' explained Werner. 'Perovsky's is a big, rather run-down club for Russians near the National Palace. The ground floor is a restaurant open to anyone. It was started after the revolution. The members used to be dukes and counts and people who'd escaped from the Bolsheviks. Now it's a pretty mixed crowd but the anti-communist line is still de rigueur. The people from the Soviet Embassy give it a wide berth. If a man such as Stinnes went in there and spoke out of turn he might never get out.'

'Really never get out?' I said.

Werner turned to look at me. 'It's a rough town, Bernie. It's not all margaritas and mariachis like the travel posters.'

'But the Kronprinz Club is not so particular about its membership?' persisted Dicky.

'No one goes there to talk politics. It's the only place in town where you can get real German draught beer and good German food,' explained Werner. 'It's very popular. It's a social club; you get a very mixed crowd there. A lot of them are transients: airline pilots, salesmen, ships' engineers, businessmen, priests even.'

'And KGB men?'

'You Englishmen avoid each other when you are abroad,' said Werner. 'We Germans like to be together. East Germans, West Germans, exiles, expatriates, men avoiding tax, men avoiding their wives, men avoiding their creditors, men avoiding the police. Nazis, monarchists, communists, even Jews like me. We like to be together because we are Germans.'

'Such Germans as Stinnes?' said Dicky sarcastically.

'He must have lived in Berlin. His German is as good as Bernie's,' said Werner, looking at me. 'Even more convincing in a way, because he has the sort of strong Berlin accent you seldom hear except in some workers' bar in the city. It was only when I began to listen to him really carefully that I could detect something that was not quite right in the background of his voice. I'll bet everyone in the club thinks he's German.'

'He's not here to get a tan,' said Dicky. 'A man like that is sent here only for something special. What's your guess, Bernard?'

'Stinnes was in Cuba,' I said. 'He told me that when we talked together. Security police. I went back to the continuity files and began to guess he was there to give the Cubans some advice when they purged some of the bigwigs in 1970. It was a big shake-up. Stinnes must have been some kind of Latin America expert even then.'

'Never mind old history,' said Dicky. 'What's he doing now?'

'Running agents, I suppose. Guatemala is a KGB priority, and it's not so far from here. Anyone can walk through; the border is just jungle.'

'I don't think that's it,' said Werner.

I said, 'The East Germans backed the Sandinista National Liberation Front long before it looked like winning and forming a government.'

'The East Germans back anybody who might be a thorn in the flesh of the Americans,' said Werner.

'But what do you really think he's doing?' Dicky asked me.

I was stalling because I didn't know how much Dicky would want me to say in front of Zena and Werner. I kept stalling. I said, 'Stinnes speaks good English. Unless the cheque book is a deliberate way of throwing us off the scent, he might be running agents into California. Handling data stolen from electronics and software research firms perhaps.' I was improvising. I didn't have the slightest idea of what Stinnes might be doing.

'Why would London give a damn about that sort of caper?' said Werner, who knew me well enough to guess that I was bluffing. 'Don't tell me London Central put out an urgent call for Stinnes because he's stealing computer secrets from the Americans.'

'It's the only reason I can think of,' I said.

'Don't treat me like a child, Bernard,' said Werner. 'If you don't want to tell me, just say so.'

As if in response to Werner's acrimony, Zena went across to the fireplace and pressed a hidden bellpush. From somewhere in the labyrinth of the apartment there came the sound of footsteps, and an Indian woman appeared. She had that chin-up stance that makes so many Mexicans look as if they are ready to balance a water jug on their heads, and her eyes were half closed. 'I knew you'd want to sample some Mexican food,' said Zena. Personally it was the last thing I'd ever want to sample, but without waiting to hear our response she told the woman we would sit down immediately. Zena used her poor Spanish with a fluent confidence that made it sound better. Zena did everything like that.