'Haydon,' he repeated to himself, no longer able to stem the tides of memory. Even the name was like a jolt. 'I'm told that you and Bill shared everything once upon a time,' said Martindale. He stared at his chubby hands, watching them shake. Too old? Impotent? Afraid of the chase? Or afraid of what he might unearth at the end of it? 'There are always a dozen reasons for doing nothing,' Ann liked to say - it was a favourite apologia, indeed, for many of her misdemeanours - 'there is only one reason for doing something. And that's because you want to.' Or have to? Ann would furiously deny it: coercion, she would say, is just another word for doing what you want; or for not doing what you are afraid of.

Middle children weep longer than their brothers and sisters. Over her mother's shoulder, stilling her pains and her injured pride, Jackie Lacon watched the party leave. First, two men she had not seen before, one tall, one short and dark. They drove off in a small green van. No one waved to them, she noticed, or even said goodbye. Next, her father left in his own car; lastly a blond good-looking man and a short fat one in an enormous overcoat like a pony blanket made their way to a sports car parked under the beech trees. For a moment she really thought there must be something wrong with the fat one, he followed so slowly and so painfully. Then, seeing the handsome man hold the car door for him, he seemed to wake, and hurried forward with a lumpy skip. Unaccountably, this gesture upset her afresh. A storm of sorrow seized her and her mother could not console her.

Peter Guillam was a chivalrous fellow whose conscious loyalties were determined by his affections. The others had been made over long ago to the Circus. His father, a French businessman, had spied for a Circus réseau in the war while his mother, an Englishwoman, did mysterious things with codes. Until eight years ago, under the cover of a shipping clerk, Guillam himself had run his own agents in French North Africa, which was considered a murderous assignment. He was blown, his agents were hanged, he entered the long middle age of the grounded pro. He devilled in London, sometimes for Smiley, ran a few home-based operations including a network of girlfriends who were not, as the jargon has it, inter-conscious and when Alleline's crowd took over he was shoved out to grass in Brixton, he supposed because he had the wrong connections, among them Smiley. That, resolutely, was how until last Friday he would have told the story of his life. Of his relationship with Smiley he would have dwelt principally upon the end. Guillam was living mainly in London docks in those days, where he was putting together low-grade Marine networks from whatever odd Polish, Russian and Chinese seamen he and a bunch of talent-spotters occasionally managed to get their hands on. Between-whiles he sat in a small room on the first floor of the Circus and consoled a pretty secretary called Mary and he was quite happy except that no one in authority would answer his minutes. When he used the phone he got engaged or no answer. He had heard vaguely there was trouble, but there was always trouble. It was common knowledge for instance that Alleline and Control had locked horns but they had been doing little else for years. He also knew, like everyone else, that a big operation had aborted in Czechoslovakia, that the Foreign Office and the Defence Ministry had jointly blown a gasket and that Jim Prideaux, head of the scalphunters, the oldest Czecho hand, and Bill Haydon's lifelong stringer, had been shot up and put in the bag. Hence, he assumed, the loud silence and the glum faces. Hence also Bill Haydon's manic anger, of which the news spread like a nervous thrill through all the building: like God's wrath, said Mary, who loved a full-scale passion. Later he heard the catastrophe called Testify. Testify, Haydon told him much later, was the most incompetent bloody operation ever launched by an old man for his dying glory, and Jim Prideaux was the price of it. Bits made the newspapers, there were parliamentary questions and even rumours, never officially confirmed, that British troops in Germany had been put on full alert.

Eventually, by sauntering in and out of other people's offices, he began to realise what everyone else had realised some weeks before. The Circus wasn't just silent, it was frozen. Nothing was coming in, nothing was going out; not at the level at which Guillam moved, anyhow. Inside the building people in authority had gone to earth and when pay day came round there were no buff envelopes in the pigeon-holes because, according to Mary, the housekeepers had not received the usual monthly authority to issue them. Now and then somebody would say they had seen Alleline leaving his club and he looked furious. Or Control getting into his car and he looked sunny. Or that Bill Haydon had resigned on the grounds that he had been overruled or undercut, but Bill was always resigning. This time, said the rumour, the grounds were somewhat different, however: Haydon was furious that the Circus would not pay the Czech price for Jim Prideaux's repatriation; it was said to be too high in agents, or prestige. And that Bill had broken out in one of his fits of chauvinism, and declared that any price was fair to get one loyal Englishman home: give them everything, only get Jim back.

Then one evening Smiley peered round Guillam's door and suggested a drink. Mary didn't realise who he was and just said 'Hullo' in her stylish classless drawl. As they walked out of the Circus side by side Smiley wished the janitors good night with unusual terseness, and in the pub in Wardour Street he said 'I've been sacked,' and that was all.

From the pub they went to a wine bar off Charing Cross, a cellar with music playing and no one there. 'Did they give any reason?' Guillam enquired. 'Or is it just because you've lost your figure?'

It was the word 'reason' that Smiley fixed on. He was by then politely but thoroughly drunk, but reason, as they walked unsteadily along the Thames embankment, reason got through to him:

'Reason as logic, or reason as motive?' he demanded, sounding less like himself than Bill Haydon, whose pre-war, Oxford Union style of polemic seemed in those days to be in everybody's ears. 'Or reason as a way of life?' They sat on a bench. 'They don't have to give me reasons. I can write my own damn reasons. And that is not the same,' he insisted as Guillam guided him carefully into a cab, gave the driver the money and the address, 'that is not the same as the half-baked tolerance that comes from no longer caring.'

'Amen,' said Guillam, fully realising as he watched the cab pull into the distance that by the rules of the Circus their friendship, such as it was, had that minute ended. Next day Guillam learned that more heads had rolled and that Percy Alleline was to stand in as nightwatchman with the title of acting chief and that Bill Haydon, to everyone's astonishment, but most likely out of persisting anger with Control, would serve under him; or as the wise ones said, over him.

By Christmas, Control was dead: 'They'll get you next,' said Mary, who saw these events as a second storming of the Winter Palace, and she wept when Guillam departed for the siberias of Brixton, ironically to fill Jim Prideaux's slot.

Climbing the four steps to the Circus that wet Monday afternoon, his mind bright with the prospect of felony, Guillam passed these events in review and decided that today was the beginning of the road back.

He had spent the previous night at his spacious flat in Eaton Place in the company of Camilla, a music student with a long body and a sad, beautiful face. Though she was not more than twenty, her black hair was streaked with grey, as if from a shock she never talked about. As another effect, perhaps, of the same undescribed trauma, she ate no meat, wore no leather and drank nothing alcoholic; only in love, it seemed to Guillam, she was free of these mysterious restraints.

He had spent the morning alone in his extremely dingy room in Brixton photographing Circus documents, having first drawn a subminiature camera from his own operational stores, a thing he did quite often to keep his hand in. The storeman had asked 'daylight or electric?' and they had a friendly discussion about film grain. He told his secretary he didn't want to be disturbed, closed his door and set to work according to Smiley's precise instructions. The windows were high in the wall. Even sitting, he could see only the sky and the tip of the new school up the road.

He began with works of reference from his personal safe. Smiley had given him priorities. First the staff directory, on issue to senior officers only, which supplied the home addresses, telephone numbers, names, and worknames of all home- based Circus personnel. Second, the handbook on staff duties, including the fold-in diagram of the Circus's reorganisation under Alleline. At its centre lay Bill Haydon's London Station like a giant spider in its own web. 'After the Prideaux fiasco,' Bill had reputedly fumed, 'we'll have no more damned private armies, no more left hand not knowing what the right hand is doing.' Alleline, Guillam noticed, was billed twice: once as Chief, once as 'Director Special Sources'. According to rumour it was those sources which kept the Circus in business. Nothing else, in Guillam's view, could account for the Circus's inertia at working level and the esteem it enjoyed in Whitehall. To these documents, at Smiley's insistence, he added the scalphunters' revised charter, in the form of an Alleline letter beginning 'Dear Guillam', and setting out in detail the diminution of his powers. In several cases, the winner was Toby Esterhase, head of Acton lamplighters, the one outstation which had actually grown fatter under lateralism.

Next he moved to his desk and photographed, also on Smiley's instruction, a handful of routine circulars which might be useful as background reading. These included a belly- ache from Admin on the state of safe houses in the London area ('Kindly treat them as if they were your own) and another about the misuse of unlisted Circus telephones for private calls. Lastly a very rude personal letter from documents warning him 'for the last time of asking' that his workname driving licence was out of date, and that unless he took the trouble to renew it 'his name would be forwarded to housekeepers for appropriate disciplinary action'.

He put away the camera and returned to his safe. On the bottom shelf lay a stack of lamplighter reports issued over Toby Esterhase's signature and stamped with the codeword 'Hatchet'. These supplied the names and cover jobs of the two or three hundred identified Soviet intelligence officers operating in London under legal or semi-legal cover; trade, Tass, Aeroflot, Radio Moscow, consular and diplomatic. Where appropriate they also gave the dates of lamplighter investigations and names of branch lines, which is jargon for contacts thrown up in the course of surveillance and not necessarily run to earth. The reports came in a main annual volume and monthly supplements. He consulted the main volume first, then the supplements. At eleven twenty he locked his safe, rang London Station on the direct line and asked for Lauder Strickland of Banking Section.