John le Carre - Our kind of traitor

And the house itself as pretty as Hector had promised, even in the downpour: a late-eighteenth-century flat-fronted terrace house of London stock brick on three floors with freshly painted white steps leading up to a newly painted door of royal blue with a fan window above it, a sash window either side of it, and basement windows to each side of the front steps.

But no separate outside basement staircase, Luke duly noted as he climbed the steps, turned the key and went inside, then stood on the doormat, first listening, then hauling off his drenched overclothes and extracting a pair of dry slip-ons from their carry-bag under his waterproof.

The hall richly carpeted in screaming deep-pile vermilion: legacy of the little turd that Jenny had rumbled just in time. An antique porter's chair in strident new green hide. A period mirror, lavishly regilded. Hector had meant to do well by his beloved Jenny, and after his successful foray against the Vulture Capitalists, he could presumably afford to. Two staircases above him, also deep-carpeted. He called out 'anyone here?' – and heard nothing. He pushed open a door to the drawing room. Original fireplace. Roberts prints, sofa and armchairs in upmarket close covers. In the kitchen, high-end equipment, distressed pine table. He pushed open the basement door and called down the stone steps: 'Hello there – excuse me' – no reply.

He climbed to the first floor without hearing his own footsteps. At the half-landing, there were two doors, the one on his left reinforced with a steel plate and brass locks either side at shoulder height. The door on his right was just a door. Twin beds not made up, small bathroom off.

A second key was attached to the house key Hector had given him. Addressing the door on his left, he turned the locks and stepped into a pitch-dark room that smelled of woman's deodorant, the one Eloise used to like. He groped for the light switch. Heavy red velvet curtains, barely hung out, tightly drawn and held together with oversized safety pins that haphazardly recalled for him his weeks of recuperation in the American Hospital in Bogota. No bed. At the centre of the room, a bare trestle table with rotating chair, computer and reading light. On the wall ahead of him, fixed into the angle of the ceiling, four black blinds of waxy cloth reaching to the floor.

Returning to the half-landing, he leaned over the bannisters and yet again called 'anyone there?' and yet again received no answer. Back in the bedroom he released the black blinds one by one, nursing them into their housings on the ceiling. At first he thought he was looking at an architect's plan, wall wide. But a plan of what? Then he thought it must be a huge piece of calculus. But calculating what?

He studied the coloured lines and read the careful italic handwriting denoting what he at first took to be towns. But how could they be towns with names like Pastor, Bishop, Priest and Curate? Dotted lines beside solid ones. Black lines turning to grey, then vanishing. Lines in mauve and blue, converging on a hub somewhere south of centre, or did they emanate from it?

And all of them with such detours, so much backtracking, so many turns, doublings and switches of direction, up, down and sideways, and then up again, that if his son, Ben, in one of his unexplained rages, had holed up in this same room and seized a tin of coloured crayons and zigzagged his way across the wall, the effect wouldn't have been much different.

'Like it?' Hector inquired, standing behind him.

'Are you sure you've got it the right way up?' Luke replied, determined not to show surprise.

'She's calling it Money Anarchy. I reckon it's just about right for the Tate Modern.'

'She?'

'Yvonne. Our Iron Maiden. Does mainly afternoons. This is her room. Yours is upstairs.'

Together, they climbed to a converted attic with stripped beams and dormer windows. One trestle table of the same design as Yvonne's. Hector is no fan of desk drawers. One desktop computer, no terminal.

'We don't use landlines, encrypted or t'other,' Hector said, with the hushed vehemence that Luke was learning to expect of him. 'No fancy hotlines to Head Office, no email connection, encrypted, decrypted or fried. The only documents we deal with are on Ollie's little orange sticks.' He was holding one up: a common memory stick with a number 7 branded on its orange plastic shell. 'Each stick tracked in transit by each of us each end, got it? Signed in, signed out. Ollie runs the shuttle, keeps the log. Spend a couple of days with Yvonne and you'll get the hang of it. Other questions as they arise. Any problems?'

'I don't think so.'

'Nor do I. So lean back, think of England, don't maunder, and don't fuck up.'

And think too of Our Iron Maiden. Professional bloodhound, balls of steel and Eloise's expensive deodorant.

*

It was advice Luke had done his utmost to adhere to for the last three months, and he prayed devoutly that he would do so today. Twice, Billy Boy Matlock had summoned him to the presence, to blandish or threaten him, or both. Twice he had ducked and weaved and lied to Hector's instruction, and survived. It had not been easy.

'Yvonne does not exist either in Heaven or here on earth,' Hector had decreed from Day One. 'Does not, will not. Got it? That's your bottom line. And your top line too. And if Billy Boy straps you by your balls to the chandelier, she still doesn't exist.'

Does not exist? A demure young woman in a long dark raincoat and pointed hood standing on the doorstep on the very first evening of his very first day here, no make-up, clutching a baggy briefcase in both arms as if she had just rescued it from the flood, does not, will not exist?

'Hi. I'm Yvonne.'

'Luke. Come on in, for Heaven's sake!'

A dripping handshake as they bundle her into the entrance hall. Ollie, the best back-door man in the business, finds a hanger for her raincoat and hangs it in the loo to drip on to the tiled floor. A three-month-long working relationship that does not exist has begun. Hector's strictures about paper did not extend to Yvonne's bulky bag, Luke quickly learned later that same night. That was because whatever she brought in her bag left in it the same day. And the reason for this again was that Yvonne was no mere researcher, she was a clandestine source.

One day her bag might contain a bulky file from the Bank of England. Another, it would be from the Financial Services Authority, the Treasury, the Serious and Organized Crime Agency. And on one momentous Friday evening, never to be forgotten, it was a stack of six fat volumes and a score of audio cassettes, enough to fill the bag to bursting, from the hallowed archives of the Government Communications Headquarters itself. Ollie, Luke and Yvonne spent the whole weekend copying, photographing and replicating the material any way they could, so that Yvonne could return it to its rightful owners at crack of dawn on Monday morning.

Whether she came by her loot licitly or by stealth, whether she filched it or cajoled it out of her colleagues and accomplices, Luke to this day had no idea. He knew only that as soon as she arrived with her bag, Ollie would whisk it to his lair behind the kitchen, there to scan its contents, transfer them to a memory stick, and return the bag to Yvonne: and Yvonne, come end of day, to whichever Whitehall department officially owned her services.

For that too was a mystery, never once revealed in the long afternoons when Luke and Yvonne sat cloistered together comparing the illustrious names of Vulture Capitalists with billion-dollar cash transfers conducted at lightning speed across three continents in a day; or chatting in the kitchen over Ollie's lunchtime soup, tomato a speciality, French onion not bad either. And his crab chowder, which he brought part-cooked in a picnic Thermos and completed on the gas stove, a miracle by common consent. But as far as Billy Boy Matlock is concerned, Yvonne does not and will not ever exist. Weeks of training in the arts of resisting interrogation say so: so does a month of crouching handcuffed in a mad drug lord's jungle redoute while your wife discovers that you are a compulsive womanizer.