'Did I ask you what you wanted with the motorcycle that day in Pankow?' he said.

It seemed a silly comparison but Rolf obviously thought it appropriate. Funny that he'd not mentioned some of the other favours he'd done for me. He hadn't risked his life but he'd risked his job for me more than once, and laying down a job for a friend comes high on my friendship scale.

He said, 'Do I get the briefcase or are you going to unpack it all here in the middle of the bus station?' As a child, I'd been intimidated by Rolf Mauser's appearance and by the big bushy eyebrows that turned up at the outer ends to give him a fierce demonic appearance. When I'd realized that he brushed his straggly eyebrows upwards to keep them out of his eyes, my fears of Rolf Mauser had vanished and I saw in him a lonely old man who liked to wallow in memories of his youth.

'Suppose I told you I had no money?' I said.

Behind us a thin Negro wielded a gigantic broom, sweeping fried chicken bones, ice-cream wrappers and brightly coloured litter before him. Rolf turned and tossed his empty paper cup into the heap as the man brushed it slowly past us. 'All British senior staff have five hundred pounds in used notes available at home at all times. That's been the regulations for years now, Bernd. We both know that.'

'The briefcase is for you.' I passed it to him.

'You were always considerate, Bernd.'

'I don't like it, Rolf.'

'Why?'

'What do you want with a gun, Rolf?'

'Who taught you to crack a safe?'

That wasn't a safe, Rolf. That strongbox where they kept the school reports could have been opened with a knife and fork.'

'My son Axel said you were a good friend, Bernd.'

'Did you need Axel to confirm it, Rolf?'

'We both know you are a good friend.'

'Or did you decide I was the only one fool enough to give you money and a gun and ask no questions?'

'Good friend. I appreciate it. We all do.'

'Who are "we all"?'

Rolf Mauser smiled. 'We all do, Bernd; me, Axel, Werner and the others. And now we owe you something.'

'Maybe,' I said cautiously. Rolf was the sort of man whose favours could get you into a lot of trouble.

He put the briefcase down on the ground and held it upright between his ankles while he undid his magnificent leather coat. When he rebuttoned it, he belted it more tightly as if he hoped that would make him warmer.

'Who is Brahms Four, Bernd? What's his name?'

'I can't tell you, Rolf.'

'Is he still in Berlin?'

'No one knows,' I said. It wasn't true of course, but it was the nearest I could go.

'Rumours say Brahms Four is not working for you any longer. We want to know if he's left Berlin.'

'What does it matter to you?' I asked.

'Because when Brahms Four is kaputt you'll pay off the Brahms network and close us down. We need to know in advance. We need to get ready.'

I looked at him for a moment without replying. Rolf Mauser's participation in Brahms was – as far as my information went – recent and minimal. Then the penny dropped: 'Because of your rackets, you mean? Because London is supplying you with things you need to keep Werner's import-export racket functioning?'

'You haven't reported that, have you, Bernd?'

'I have enough of my own problems without trying to find more,' I said. 'But London Central aren't here to help you run rackets in East Germany, or anywhere else.'

'You didn't always talk that way, Bernd. I remember a time when everyone agreed that Brahms was the best source in Berlin System. The best by far.'

'Times change, Rolf.'

'And now you'd throw us to the wolves?'

'What are you saying?'

'You think we don't know that you have a KGB spy here in London Central. Brahms net is going to be blown any minute.'

'Who says so? Did Werner say it? Werner is not a member of the network. He's not employed by the Department at all. Do you know that?'

'It doesn't matter who said it,' replied Rolf.

'So it was Werner. And we both know who told him, don't we, Rolf?'

'I don't know,' said Rolf staunchly, although his eyes said different.

'That bloody wife of his. That bloody Zena,' I said. I cursed Frank Harrington and his womanizing. I knew Frank too well to suspect him of revealing to her anything really important. But I'd seen enough of Zena Volkmann to know that she'd trade on her relationship with Frank. She'd make herself sound important. She'd feed Werner any wild guesses, rumours and half-truths. And Werner would believe anything he heard from her.

'Zena worries about Werner,' said Rolf defensively.

'You must be very stupid, Rolf, if you really believe that Zena worries about anything but herself.'

'Perhaps that's because no one else worries about her enough,' said Rolf.

'You'll break my bloody heart, Rolf,' I said.

I'm afraid we parted on a note of acrimony. When I looked back, he'd still not boarded the bus. I suspected that he had no intention of boarding any bus. Rolf Mauser could be a devious devil.

Some of the most secret conversations I'd ever heard took place not in any of the debugged 'silent rooms' under the Department's new offices but in restaurants, St James's clubs or even in the backs of taxicabs. So there was nothing surprising about Dicky Cruyer's suggestion that I go to his house about nine 'for a confidential chat'.

A man repairing the doorbell let me in. Dicky's wife, Daphne, was working at home that morning. A large layout pad occupied most of the corner table in the front room. A jam jar of coloured felt-tip pens was balanced on the TV, and scattered across the sofa were scribbled roughs for advertising a new breakfast food. Daphne's art-school training was everywhere evident; brightly painted bits of folk art and crudely woven cushion covers, a primitive painting of Adam and Eve over the fireplace and a collection of matchbox covers displayed in an antique cabinet. The only personal items in the room were photos: a picture of the Cruyers' two sons amid a hundred other grim-faced, grey-uniformed boys in front of the huge Gothic building that was their boarding school; and, propped on the mantelshelf, a large shiny colour photo of Dicky's boat. There was some very quiet Gilbert and Sullivan leaking out of the hi-fi. Dicky was humming.

Through the 'dining area' I could see Daphne in the kitchen. She was pouring hot milk into large chinaware mugs. Looking up she said 'Ciao!' with more than her usual cheerfulness. Did she know her husband had been having an affair with my sister-in-law? Her hair was that straggly mess that only comes from frequent visits to very expensive hairdressers. From what little I knew about women, that might have been a sign that she did know about Dicky and Tessa.

'Traffic bad?' said Dicky as I threw my raincoat onto a chair. It was his subtle way of saying I was late. Dicky liked to have everyone on the defensive right from the start. He'd learned such tactics in a book about young tycoons. I secretly borrowed it from his office bookshelf one weekend so that I could read it too.

'No,' I lied. 'It only took me ten minutes.'

He smiled and I wished I'd not got into the game.

Daphne brought cocoa on a dented tin tray advertising Pears soap. My cup celebrated the silver jubilee of King George V. Dicky complimented Daphne on the cocoa and pressed me to have a biscuit, while she gathered up her pens and paper and retreated upstairs. I sometimes wondered how they managed together; secret intelligence was a strange bedfellow for a huckster. It was better to be married to a Departmental employee; I didn't have to ask her to leave the room every time the office came through on the phone.

He waited until he heard his wife go upstairs. 'Did I tell you the Brahms network was going to fall to pieces?'