A low cottonwool sky hung over the imported palaces, making them dreary in their fancy dress. Summer music played in the parks but the summer clung behind the clouds, leaving a chalky Nordic mist to trick and tremble on the Venetian waterways. Barley walked and, as always when he was in Leningrad, he had the sensation of walking through other cities, now Prague, now Vienna, now a bit of Paris or a corner of Regent's Park. No other city that he knew hid its shame behind so many sweet façades or asked such terrible questions with its smile. Who worshipped in these locked, unreal churches? And whose God? How many bodies had choked these graceful canals or floated frozen to the sea? Where else on earth has so much barbarism built itself such pretty monuments? Even the people in the street, so slow spoken, decorous, reserved, seemed joined to one another by their monstrous dissembling. And Barley, as he loitered and gazed like any tourist – and like any spy counted off the minutes – Barley felt himself a part of their duplicity.

He had shaken hands with an American tycoon who was not a tycoon, and commiserated with him about his sick wife who was not sick and probably not his wife.

He had instructed a subordinate who was not his subordinate to give succour in an emergency that did not exist.

He was on his way to keep a rendezvous with an author who was not an author but was seeking martyrdom in a city where martyrdom could be had free across the counter, whether or not you happened to stand in line for it.

He was scared numb and had a hangover for the fourth day running.

He was a citizen of Leningrad at last.

Finding himself in the Nevsky Prospekt he realised he was looking for the cafeteria called informally the Saigon, a place for poets, drug-pedlars and speculators, not professors' daughters. 'Your father is right,' he heard her say. 'The system will always win.'

He had his own street map, courtesy of Paddy – German, with a multi-lingual text. From Cy he had a copy of Crime and Punishment , a battered Penguin paperback in a translation to drive him to despair. He had put them both in a plastic carrierbag. Wicklow had insisted. Not just any bag but this bag, advertising some beastly American cigarette and recognisable at five hundred metres. Now his only mission in life was to trail Raskolnikov on his fateful journey to murder the old lady, which was why he was searching for a courtyard leading off the Griboyedev Canal. Iron gates opened to it, a spreading tree gave it shade. He wandered in it slowly, peering at his Penguin book, then guardedly at the grimy windows as if expecting the old pawnbroker's blood to come seeping down the yellowing paintwork. Only occasionally did he allow his gaze to stray into that unfocused middle distance which is the preserve of the English upper classes, and which comprises such extraneous objects as passers-by, or those not passing by but doing nothing; or the gate that led to Plekhanova Street which only very local people knew of, said Paddy, such as scientists who in their youth had studied at the Litmo around the corner, but who, so far as Barley could see from his casual searching of the approaches, showed no sign of returning.

He was out of breath. A bubble of nausea like an air pocket filled his lower chest. He reached the gate and opened it. He passed through an entrance hall. He climbed the short flight of steps to the street. He glanced both ways and made another show of comparing his findings while Wicklow's hated microphone harness sawed his back. He turned round and sauntered back through the courtyard and under the spreading tree until he was once more alongside the canal. He sat on a bench and unfolded the street map. Ten minutes, Paddy had said, handing him a scratched sports-watch in place of his unreliable heirloom. Five before, five after, then abort.

'You are lost?' asked a pale man who looked too old to be a tout. He was wearing Italian racing-driver glasses and Nike sneakers. His Russian English had an American accent.

'I'm always lost, old boy, thank you,' said Barley politely. 'It's the way I like it.'

'You want to sell me something? Cigarettes? Scotch? Fountain pen? You want to trade drugs or currency or something like this?'

'Thanks, but I'm very nice as I am,' Barley replied, relieved to hear himself speaking normally. 'If you'd just move out of the sun a little, I'll be even nicer.'

'You want to meet an international group of people including girls? I can show you the real Russia nobody ever gets to see.'

'Old boy, to be perfectly honest, I don't believe you'd know the real Russia if it got up and bit you in the balls,' said Barley, returning to his map. The man drifted away.

On Fridays even the great scientists will be doing what everyone else is doing, Paddy had said. They'll be closing down the week and getting drunk. They'll have had their three-day knees-up, they'll have shown each other their achievements and traded their researches. Their Leningrad hosts will be feeding them a lavish lunch but leaving them time to get at the shops before they return to their postbox numbers. That will be your friend's first chance to slip away from the group if he's going to.

My friend. My Raskolnikov friend. Not his friend. Mine. In case I come unstuck.

One rendezvous down and two to go.

Barley stood up, rubbed his back and with time to waste continued his literary tour of Leningrad. Recrossing the Nevsky Prospekt, he gazed at the weathered faces of the shoppers and in a rush of empathy prayed to be assumed into their ranks: 'I'm one of you! I share your confusions! Accept me! Hide me! Ignore me!' He steadied himself. Look round. Look foolish. Gawp.

Behind him stood the Kazan Cathedral. Ahead of him rose the House of Books, where as a good publisher Barley now lingered, squinting into the windows and upward at the stubby tower with its vile globe. But he did not stay for long in case he was recognised by somebody from one of the editorial offices upstairs. He entered Zhelyabova Street and approached one of the great department stores of Leningrad, with its wartime English fashions in the window and fur hats out of season. He placed himself conspicuously at the main entrance, hooking the carrier bag over his middle finger and unfolding his map for refuge.

Not here, he thought. For Christ's sake, not here. Give us a decent privacy, Goethe, please. Not here.

'If he selects the shop, he's reckoning on a very public meeting,' Paddy had said. 'He's got to fling up his arms and shout, "Scott Blair, can it be you?"'

For the next ten minutes Barley thought of nothing. He stared at the map, lifted his head and stared at buildings. He stared at girls, and in Leningrad that summer's day the girls were staring back. But their alertness did not reassure him and he ducked back into his map. Sweat was running like marbles over his rib cage. He had a fantasy that the microphones would short-circuit. Twice he cleared his throat because he feared he wouldn't be able to speak. But when he tried to moisten his lips he discovered that his tongue had withered.

The ten minutes were up but he waited another two because he owed them: to himself, to Katya, to Goethe. He folded the map, not making the right folds, but then he had never managed that anyway. He stuffed the map into the gaudy plastic bag. He rejoined the crowds and discovered that after all he could walk like everybody else, no sudden lurches, no bone-cracking falls headlong to the pavement.

He strolled back down the Nevsky towards the Anichkov Bridge, looking for the No. 7 trolleybus to Smolny for his third and final appearance before the assembled spies of Leningrad.

Two boys in jeans stood ahead of him in the queue. Three babushkas stood behind him. The trolleybus arrived and the boys leapt in. Barley followed them aboard. The two boys chatted noisily. An old man stood up in order to let one of the babushkas sit. We're a good crowd in here, Barley thought in another lurch of dependence upon those he was deceiving; let's stay together all day and enjoy each other. A small boy was frowning into his face, asking him something. On an inspiration, Barley pulled back his sleeve and showed him Paddy's steel wristwatch. The boy studied it and gave a hiss of rage. The trolleybus clanged to a halt.

He's funked it, thought Barley in relief as he entered the park. The sun broke clear of the clouds. He's chickened and who can blame him?

But by then he had spotted him. Goethe, precisely as advertised. Goethe, the great lover and thinker, seated on the third bench to your left as you enter the gravel path, a nihilist who takes no principle for granted.

Goethe. Reading his newspaper. Sober and half his original size, dressed in a black suit certainly, but looking like his smaller, older brother. Barley's heart sank, then leapt, at the sight of such sheer ordinariness. The shadow of the great poet was extinct. Lines of age marked the oncesmooth face. The mercurial had no place in this clerkish, bearded Russian taking his midday air on a park bench.

But Goethe nonetheless, and seated amid a cluster of warring Russian shrines: not a pistol shot from the fiery statues of Marx, Engels and Lenin, who forced their bronze scowls on him from strangely separated plinths; not a musket shot from the sacred Room Sixty-Seven, where Lenin had set up his revolutionary headquarters in a boarding school for the better class of Petersburg girl; not a funeral march from Rastrelli's blue baroque cathedral built to ease the declining years of an empress; not a blindfold walk from the Leningrad Party Headquarters with its oversize policemen glowering at the liberated masses.

Smola means tar, Barley recalled stupidly in this continuing moment of monstrous normality. In Smolny, Peter the Great stored his tar for the first Russian navy.

Those nearest to Goetbe were as normal as the man himself. The day might have started dull but the new sunlight had worked miracles and the good citizens were stripping off as if a common urge had seized them. Boys bare to the waist, girls like thrownaway flowers, hulking women in satin brassieres lay sprawled at Goethe's feet, playing radios, munching sandwiches and discussing whatever it was that made them grimace, ponder and laugh in swift succession.

A chip path ran close to the bench. Barley launched himself upon it studying the Informationen at the back of the folded map. In the field, Ned had said, in a session devoted to the macabre etiquette of tradecraft, the source is the star and the star decides whether to make the meeting or abort.

Fifty yards separated Barley from his star but the path joined them like a ruled line. Was he walking too fast or too slowly? One moment he was pressing up against the couple in front of him, the next he was being shoved aside from behind. If he ignores you, wait five minutes then try a second pass, Paddy had said. Squinting over his map, Barley saw Goethe's face lift as if he had scented his approach. He saw the whiteness of his checks and the unlit hollows of his eyes; then the whiteness of the newspaper -as he folded it together like a camper's blanket. He saw that there was something angular and not quite reconciled about his movements, so that he resembled in Barley's racing mind a figure of over-orderly clockwork in a Swiss town: now I will lift my white face, now I strike twelve with my white flag, now I stand up and march away. The newspaper folded, Goethe put it in his pocket and gave a pedagogic glance at his wristwatch. Then with the same mechanical air of being someone else's invention, he took his place in the army of pedestrians and loped among them towards the river.