'Save some of that coffee for me, Rolf,' I complained.

He stopped filling his cup, and looked up and grinned at me. 'Suppose you find he doesn't exist?' he said, pouring the last of the coffee into my cup, dregs and all. 'Suppose you find he's just a postbox in the KGB building and you've been made a fool of for years and years?'

'Is that your guess, Rolf?'

He bit off a mouthful of roll and chewed it. 'No. I'm just being devil's advocate.'

Rolf Mauser was right: although not a Department employee, I trusted Werner Volkmann more than anyone Berlin Station could provide. He had a car he used on the East side of the Wall. He was waiting for me at that part of Schönhauserallee where the underground trains come up into the daylight and rattle along the antiquated construction that patterns the whole street with shadows.

I opened the door and got in beside him. Without a word of greeting, he started up and headed north.

'No wonder Brahms Four is getting jumpy,' I said. 'Too many people are becoming curious about him.'

'He'll not go undetected for another six months,' said Werner.

' London were hoping to squeeze another two years out of him.'

He made a noise that expressed his contempt for London Central and all then: plans and ambitions. 'With Brahms network channelling his reports?'

'Other ways could be tried,' I said.

'Such as VHF radio, just powerful enough to transmit to Olympia Stadion?' said Werner with an unmistakable edge to his voice.

'That was mentioned,' I admitted. It had been Dicky's one and only contribution to a very long meeting the previous month.

'By a fool,' said Werner.

'But what's the alternative? Putting him into a different network?'

'It could be done, couldn't it?'

'You've never had a job of introducing an agent into a network,' I said. 'Most of the nets are run by temperamental prima donnas. I couldn't face all the arguments and anxieties that go with these damned shotgun marriages.'

'Put him in contact with another network and you'll slow up the delivery,' said Werner. He was guessing, of course; he had no knowledge of what other networks we had with access to Berlin. But in fact his guess was right. There are lots of men like Werner; they just can't stop working, pay or no pay. It was probably Werner who'd held Brahms together so long.

'And you increase the number of people who know he exists,' I said.

'Does he exist?' said Werner. 'Sometimes I wonder.'

'Have you been talking to Rolf Mauser?'

'Of course I have,' admitted Werner. 'Do you imagine the network can handle material for years and not wonder where it's coming from? Especially when we get bombarded with priority demands for immediate handling.'

'I'm seeing him as soon as possible,' I said.

Werner looked away from the road for long enough to study my face. 'You're sharing secrets today, are you? That's out of character, Bernie. Why would you tell me you're seeing him?'

'Because you've guessed already.'

'No, no, no,' said Werner. 'That's not it.'

'Because we might have to get him out of East Berlin fast, Werner.'

'I'll take you to wherever you want to go,' offered Werner. 'Downtown? I have nothing to do.'

'I'll need the car, Werner. You've got plenty to do. I want you to take the London flight and be back here by evening.'

'What for?'

'When it happens, it will happen very fast.'

'When what happens?'

'Suppose, Werner…' It was hard saying it out loud. 'Suppose it's Fiona who's the KGB agent in London.'

'Your wife?'

'Well, think about it. Everything fits: the Giles Trent fiasco, and the way she tried to pin the leak of that Karlshorst signal on him. Bret wasn't in Berlin at the time in question. Dicky never saw the signal. Fiona is the only one in the right place at the right time, every time.'

'You can't be serious, Bernie.'

'I want to be wrong, Werner. But if it is Fiona and she decides to run for it, she'll take the children too.' I wanted him to say I was talking nonsense.

'But, Bernie, the duty officer at the airport would probably recognize her. Going out alone, she could say she was working. But with two kids I'd say any airport duty officer would be bound to check back with the office before letting her through.'

'So what will she do?' I said.

'If she really is KGB, she'll have them arrange about getting your children out separately. Jesus, Bernie. It's too awful to think about. It couldn't be Fiona, could it?'

'We'll have to trust Dicky,' I said. 'He'll give you whatever you need. Take the children over to my mother. Make it all sound normal. I don't want Fiona to know I suspect her. But have someone with them all the time – guards, I mean, people who will know what has to be done, not just security men – and arrange things so I can swear I know nothing about it, Werner. Just in case I'm wrong about Fiona.'

'I'm sure you're wrong about her, Bernie.'

'You'd better get going. I'll drop you at a taxi rank and then take your car. I've got a busy day. See you at Rolf's tonight.'

'I'm sure you're wrong about Fiona,' said Werner, but every time he said it he sounded less and less convinced that I was wrong.

23

I went to see Brahms Four at his office in Otto-Grotewohl-Strasse. It used to be Wilhelmstrasse in the old days, and just down the street beyond the Wall it still was. The building too had changed its name, for this was the huge and grandiose Air Ministry block that Hermann Goring had built for his bickering bureaucrats. It was one of the few Nazi government buildings that survived the fighting here in the centre of the city.

After filling in the requisite form for the clerk on the reception desk, I was shown upstairs. Here was the man who'd come back from what Dicky described as 'some godforsaken little place in Thüringerwald' to dig me out of my hideout in a narrow alley behind the Goethe Museum in Weimar just minutes before they came to get me. I'd never forget it.

Goodness knows what clerk in London Central had named the network Brahms or by what chance this man had become its number 4. But it had been put on his documents decades ago and, for their purposes, it was his name still. His real name was Dr Walter von Munte but, living in the proletarian state of the German Democratic Republic, he'd long since dropped the 'von'. He was a tall gloomy man of about sixty, with a lined face, gold-rimmed glasses and grey closely cropped hair. He was frail-looking despite his size, and his stooped shoulders and old-fashioned good manners made him seem servile by the standards of today's world. The black suit he wore was carefully pressed but, like the stiff collar and black tie, it was well worn. And he wrung his hands like a Dickensian undertaker.

'Bernd,' he said. 'I can't believe it's you… after all these years.'

'Is it so long?'

'You were not even married. And now, I hear, you have two children. Or have I got it wrong?'

'You've got it right,' I said. He was standing behind his desk watching me as I went over to the window. We were close to the Wall: here I could almost see the remains of Anhalter railway station; perhaps from a higher floor I'd see the Café Leuschner. I carelessly touched the telephone junction box on the windowsill, and glanced up at the light fittings before going back again.

He guessed what I was doing. 'Oh, you need not worry about hidden microphones here. This office is regularly searched for such devices.' He smiled grimly.

Only when I sat down on the moulded plastic chair did he sit down too. 'You want to get out?' I said softly.

'There is not much time,' he said. He was very calm and matter of fact.

'What's the hurry?'