There was plenty of work waiting for me in the office. At the top of the pile, flagged and beribboned, was a Ministry of Defence request for details of Semtex, a Czechoslovak explosive exported through the DDR and now being used in home made 'bean can grenades' and causing casualties in Northern Ireland. Under it there were some confidential questions about the Leipzig Trade Fair and – with only a number one priority – some supplements from the Minister that must be ready for parliamentary question time.

It was one of the natural laws of departmental life that the sort of files that Dicky chose to keep on his desk, while he worried about his career and vacillated about expedient courses of action, were always the ones that ultimately required the most urgent response from me when he finally dumped them on my desk. My work was not made easier by the cryptic thoughts and instructions that Dicky shared with me as each flat file was dropped into my tray.

'Just keep it warm until we hear who's going to be on the committee,' Dicky would say. Or, 'Tell the old bastard to get stuffed but keep him sweet'; 'This might work out if they find the right people but make sure it doesn't bounce back our way'; and his standard reaction: 'Find out what they really expect and maybe we'll be able to meet them halfway'. These were the sort of arcane instructions I was trying to implement on Tuesday while Dicky was gone to wherever he went when there was work in the offing. And Dicky wanted everything done by the end of the day.

By the time a debonair Frank Harrington looked into my little office and invited me to go for a quick lunch, I was glassy-eyed. 'You'll do yourself an injury if you try and work your way through this lot before going home,' said Frank, running the tip of an index finger across the cover of a fat file for which some unfortunate had analysed, in considerable detail, the various types of East European shops where only Western currency was accepted. Here were tables and estimates, comments and balance sheets, from Pewex in Poland, Tuwex in Czechoslovakia, Korekom in Bulgaria, compared point by point with Intershops in East Germany.

Without picking it up, Frank flicked open the file carefully so as not to get his hands dirty. 'Would you believe I saw this in the tray on the old man's desk on the day I got the Berlin job?'

'Of course I would,' I said.

'It's got fatter over the years, of course,' said Frank, who probably wanted to be congratulated on his phenomenal memory. He hooked his tightly rolled umbrella on the desk edge and then consulted his gold pocket watch as if to confirm that it was lunch time. 'Heave all this aside, Bernard. Let me buy you a pint of Guinness and a pork pie.' The illusion that Englishmen wanted a pub lunch every day was something that many expatriates cherished, so I smiled. Frank was looking very trim. He had been upstairs talking to the Deputy and was dressed in a three-piece grey worsted with gold watch-chain, wide-striped Jermyn Street shirt and a new Eton tie, of. which Frank seemed to have an inexhaustible supply.

My tie was plain and polyester, and my watch Japanese and plastic. I was weary and my ears were ringing with the sound of Dicky's voice. I'd been listening to the dictating machine, taking notes from a long rambling disquisition that Dicky had passed to me to 'get into shape'. It was going to be a long job. Dicky was not good at getting his arguments into proper order, and those passages where he was consistent and logical were riddled with inaccurate 'facts'. I pushed the work aside and said, 'What about next week, Frank? I'm in Berlin on Wednesday.'

Frank didn't leave. 'A very quick lunch, Bernard.'

I looked up to see him standing in the doorway with a forced smile on his face. It wasn't until then I realized how much such little things meant to him.

I knew of course that Frank had always looked upon me as a surrogate son. Several people had remarked on it, usually at times when I was being especially rude or making Frank's life difficult. Even Frank himself had more than once referred to some undefined responsibility he'd owed to my father. But Frank took it too seriously. More than once he'd risked his career to help me, and to tell the truth that made me uncomfortably indebted to him. Father-son relationships seldom run smoothly, and true to my role I'd taken considerably more from him than I ever gave, and I confess I resented being obliged to anyone, even Frank.

'You're right, Frank. To hell with it!' I took the tape cassette from the machine and locked it in my desk drawer. Maybe I should have sent it to the KGB to promote more confusion amongst the opposition. Frank reached for my coat.

Frank always had a car and driver during his visits to London. It was one of the desirable perks of his job in Berlin. We went off to a 'small City wine bar'; but because this was Frank Harrington's idea, the bar was not in the City. It was south of the Thames in that borough of London which is enigmatically called the 'the Borough'. In a street of rundown Victorian houses off the Old Kent Road its entrance was a doorway marked only by a small polished brass plate of the sort that marks the offices of lawyers and dentists. A long underground corridor eventually opened upon a gloomy cellar with heavy pillars and low vaulting. The brickwork was painted a shiny bottle-green. Small blackboards were chalked with tempting vintage wines that were today available by the glass. A bar counter occupied most of one wall of the largest 'room' and in the adjoining areas spotlights picked out small tables where shrill businessmen drank their vintage clarets and ports, nibbled at their expensive cold snacks and tried to look like tycoons avoiding the TV crews while concluding multi-million dollar City deals.

'Like it?' said Frank proudly.

'Wonderful, Frank.'

'Charming little place, eh? And no chance of meeting any of our people here, that's what I like about it.' By 'our' people he meant important Whitehall bureaucrats. He was right.

An old man dressed in appropriate wine cellar style – white shirt, bow tie and long apron – showed us to places set ready at the counter. Frank was obviously known and welcomed there, and when I saw how much he spent on a bottle of Chateau Palmer 1966 I could understand why. But Frank's discursive survey of the wine list, and its extravagant outcome, was part of the paternal role he had to demonstrate.

With due ceremony the bottle was opened, the cork sniffed. Poured, swirled and tasted. Frank puckered his lips, bared his teeth and pronounced it 'drinkable'. We laughed.

It was another immutable aspect of Frank's character that, along with his superlative wine, he ate, without adverse comment, yellowing Stilton, a desiccated hunk of pork pie and squashy white bread.

I could see he had something to tell me, but I contributed my share of office small-talk and let him take his time. When he'd eaten his segment of pork pie – each mouthful spread with a large dollop of fierce English mustard – he poured a second glass of claret for both of us and said, 'That bloody Zena.' He said it quietly but with feeling. 'I could kill her.'

I looked at him with interest. In the past Frank had always indulged Zena. Infatuated was the only word for it. 'Is she all right?' I asked casually between pieces of pork pie. 'She was off to Frankfurt an der Oder, the last I heard of her. Werner was worried.'

He looked at me as if trying to decide how much I knew, and then said, 'She was running up and down on the Berlin-Warsaw express.'

'The "paradise train"? What for?' I asked but I'd already guessed the answer.

'Black market. You've been on that train: you know.'

Yes, I'd been on that train and I knew. Once over the Polish border it became an oriental bazaar. Black-market traders – and in the subtle nuances of East Bloc social life, brown – and grey-market traders too – moved from compartment to compartment buying and selling everything from Scotch whisky to Black & Decker power tools. I remember loud Polish voices and hands waving bundles of dollar bills and suitcases almost bursting with pop music records and cartons of Marlboro cigarettes. The 'paradise train' would provide plenty of opportunities to buy rare artefacts and manuscripts. 'What was Zena doing on the train?' I asked.