'Good shot, Bret,' said Silas. 'So none of them have ever met him?' He smoked his cigar and blew smoke at Cruyer. 'Or have I misunderstood?'

'Bernard's the only one who ever worked with him,' admitted Cruyer, taking off his jacket and placing it carefully on the back of an empty chair. 'I can't even get a recent photo of him.'

'Brahms Four.' Silas scratched his belly. 'He's almost my age, you know. I knew him back when Berlin was Berlin. We shared girlfriends and fell down drunk together. I know him the way you only know men you grew up with. Berlin! I loved that town.'

'As well we know,' said Cruyer with a touch of acid in his voice. He cleared the pocket and rolled the balls back along the table.

'Brahms Four tried to kill me at the end of 1946,' said Silas, ignoring Cruyer. 'He waited outside a little bar near the Alexanderplatz and took a shot at me as I was framed against the light in the doorway.'

'He missed?' said Cruyer with the appropriate amount of concern.

'Yes. You'd think even an indifferent shot would be able to hit a big fellow like me, standing full-square against the light, but the stupid bastard missed. Luckily I was with my driver, a military policeman I'd had with me ever since I'd arrived. I was a civilian in uniform, you see – I needed a proper soldier to help me into my Sam Browne and remind me when to salute. Well, he laid into Brahms Four. I think he would have maimed him had I not been there. The corporal thought he'd aimed at him, you see. He was damned angry about it.'

Silas drank a little port, smoked his cigar, and watched my inexpert stroke in silence. Cruyer dutifully asked him what had happened after that.

'The Russkies came running. Soldiers, regimental police, four of them, big peasant boys with dirty boots and unshaven chins. Wanted to take poor old Brahms Four away. Of course, he wasn't called Brahms Four then, that came later. Alexanderplatz was in their sector even if they hadn't yet built their wall. But I told them he was an English officer who'd had too much to drink.'

'And they believed you?' said Cruyer.

'No, but your average Russian has grown used to hearing lies. They didn't believe me but they weren't about to demonstrate a lot of initiative to disprove it. They made a feeble attempt to pull him away, but my driver and I picked him up and carried him out to our car. There was no way the Russians would touch a vehicle with British Army markings. They knew what would happen to anyone meddling with a Russian officer's car without permission. So that's how we brought him back to the West.'

'Why did he shoot at you?' I asked.

'You like that brandy, do you,' said Silas. 'Twenty years in the wood; it's not so easy to get hold of vintage brandy nowadays. Yes – well, he'd been watching me for a couple of days. He'd heard rumours that I was the one who'd put a lot of Gehlen's people in the bag, and his closest friend had got hurt in the roundup. But we talked about old times and he saw sense after a while.' I nodded. That vague explanation was Silas's polite way of telling me to mind my own business.

We watched Bret Rensselaer play, pocketing the red ball with a perfectly angled shot that brought the white back to the tip of his cue. He moved his position only slightly to make the next stroke. 'And you've been running him since 1946?' I said, looking at Silas.

'No, no, no,' said Silas. 'I kept him well away from our people in Hermsdorf. I had access to funds and I sent him back into the East Sector with instructions to lie low. He was with the Reichsbank during the war – his father was a stockbroker – and I knew that eventually the regime over there – Communist or not – would desperately need men with top-level banking experience.'

'He was your investment?' said Cruyer.

'Or, you might say, I was his investment,' said Silas. The game was slower now, each man taking more time to line up his shot as he thought about other things. Cruyer aimed, missed and cursed softly. Silas continued, 'We were both going to be in a position to help each other in the years ahead. That much was obvious. First he got a job with the tax people. Ever wondered how Communist countries first become Communist? It's not the secret police who do the deed, it's the tax collectors. That's how the Communists wiped out private companies: they increased the tax rate steeply according to the number of employees. Only firms with less than a dozen employees had a chance of surviving. When they'd destroyed private enterprise, Brahms Four was moved to the Deutsche Emissions und Girobank at the time of the currency reform.'

Dicky smiled triumphantly at me as he said to Silas, 'And that later became the Deutsche Notenbank.' Good guess, Dicky, I thought.

'How long was he a sleeper?' I asked.

'Long enough,' said Silas. He smiled and drank his port. 'Good port this,' he said, raising his glass to see the colour against the light from the window. 'But the bloody doctor has cut me back to one bottle a month – one bottle a month, I ask you. Yes, he was a sleeper all through the time when the service was rotten with traitors, when certain colleagues of ours were reporting back to the Kremlin every bloody thing we did. Yes, he was lucky, or clever, or a bit of both. His file was buried where no one could get at it. He survived. But, by God, I activated him once we'd got rid of those bastards. We were in bad shape, and Brahms Four was a prime source.'

'Personally?' said Dicky Cruyer. 'You ran him personally'?' He exchanged his cue for another, as if to account for his missed stroke.

'Brahms Four made that a condition,' said Silas. 'There was a lot of that sort of thing at that time. He reported to me personally. I made him feel safer and it was good for me too.'

'And what happened when you were posted away from Berlin?' I asked him.

'I had to hand him over to another Control.'

'Who was that?' I asked.

Silas looked at me as if deciding whether to tell me, but he had already decided; everything was already decided by that time. 'Bret took over from me.' We all turned to look anew at Bret Rensselaer, a dark-suited American in his middle fifties, with fair receding hair and a quick nervous smile. Bret was the sort of American who liked to be mistaken for an Englishman. Recruited into the service while at Oxford on a Rhodes scholarship, he'd become a dedicated Anglophile who'd served in many European stations before taking over as Deputy Controller of the European Economics desk, which later became the Economics Intelligence Committee and was now Bret's private empire. If Brahms Four dried up as a source, Bret Rensselaer's empire would virtually collapse. Little wonder he looked so nervous.

It was Bret's shot again. He balanced his cue as if checking its weight, then reached for the resin. 'I ran Brahms Four for years on a personal basis, just as Silas had done before me.'

'Did you ever meet him face to face?' I asked.

'No, I never went across to the East, and as far as I know, he never came out. He knew only my codename.' He finally finished with the resin and placed it carefully on the ledge of the scoreboard.

'Which you'd taken from Silas?' I said. 'What you're saying is that you carried on pretending to be Silas.'

'Sure I did,' said Bret, as if he'd intended to make this clear from the start. The only thing field men hate more than a Control change is a secret Control change with a name switch. It wasn't something any desk man would boast about. Bret had still not made his shot. He stood facing me calmly but speaking a little more rapidly now that he was on the defensive. 'Brahms Four related to Silas in a way no newcomer could hope to do. It was better to let him think his stuff was still coming to Silas.' He leaned over the table to make his shot. Characteristically it was faultless and so was his next, but the third pot went askew.