Esterhase pursed his lips and frowned a little, as if to say he never discussed a superior.

'Whereas Gerald is an expert on those things. His operational life has been spent weaving and ducking round the Eastern markets. Percy's out of his depth but keen. Gerald's on his home ground. This Russian source, says Gerald, could be the richest the Circus has had for years. Gerald doesn't want to say too much but he expects to be getting some trade samples in a day or two and when he does, he'd like Percy to run his eye over them just to get a notion of the quality. They can go into source details later. "But why me?" says Percy. "What's it all about?" So Gerald tells him. "Percy," he says. "Some of us in the regional sections are worried sick by the level of operational losses. There seems to be a jinx around. Too much loose talk inside the Circus and out. Too many people being cut in on distribution. Out in the field, our agents are going to the wall, our networks are being rolled up or worse, and every new ploy ends up a street accident. We want you to help us put that right." Gerald is not mutinous, and he's careful not to suggest that there's a traitor inside the Circus who's blowing all the operations, because you and I know that once talk like that gets around the machinery grinds to a halt. Anyway the last thing Gerald wants is a witch-hunt. But he does say that the place is leaking at the joints, and that slovenliness at the top is leading to failures lower down. All balm to Percy's ear. He lists the recent scandals and he's careful to lean on Alleline's own Middle East adventure, which went so wrong and nearly cost Percy his career. Then he makes his proposal. This is what he says. In my thesis, you understand; it's just a thesis.'

'Sure, George,' said Toby, and licked his lips.

'Another thesis would be that Alleline was his own Gerald, you see. It just happens that I don't believe it: I don't believe Percy is capable of going out and buying himself a top Russian spy and manning his own boat from then on. I think he'd mess it up.'

'Sure,' said Esterhase, with absolute confidence.

'So this, in my thesis, is what Gerald says to Percy next. "We - that is, myself and those like-minded souls who are associated with this project - would like you to act as our father-figure, Percy. We're not political men, we're operators. We don't understand the Whitehall jungle. But you do. You handle the committees, we'll handle Merlin. If you act as our cut- out, and protect us from the rot that's set in, which means in effect limiting knowledge of the operation to the absolute minimum, we'll supply the goods." They talk over ways and means in which this might be done, then Gerald leaves Percy to fret for a bit. A week, a month, I don't know. Long enough for Percy to have done his thinking. One day Gerald produces the first sample. And of course it's very good. Very, very good. Naval stuff as it happens, which couldn't suit Percy better because he's very well in at the Admiralty, it's his supporters' club. So Percy gives his naval friends a sneak preview and they water at the mouth. "Where does it come from? Will there be more?" There's plenty more. As to the identity of the source - well that's a big, big mystery at this stage, but so it should be. Forgive me if I'm a little wide of the mark here and there but I've only the file to go by.'

The mention of a file, the first indication that Smiley might be acting in some official capacity, produced in Esterhase a discernible response. The habitual licking of the lips was accompanied by a forward movement of the head and an expression of shrewd familiarity, as if Toby by all these signals was trying to indicate that he too had read the file, whatever file it was, and entirely shared Smiley's conclusions. Smiley had broken off to drink some tea.

'More for you, Toby?' he asked, over his cup.

'I'll get it,' said Guillam with more firmness than hospitality. 'Tea, Fawn,' he called through the door. It opened at once and Fawn appeared on the threshold, cup in hand.

Smiley was back at the window. He had parted the curtain an inch, and was staring into the square.

'Toby?'

'Yes, George?'

'Did you bring a babysitter?'

'No.'

'No one?'

'George, why should I bring babysitters if I am just going to meet Peter and a poor Pole?' Smiley returned to his chair. 'Merlin as a source,' he resumed. 'Where was I? Yes, well conveniently Merlin wasn't just one source, was he, as little by little Gerald explained to Percy and the two others he had by now drawn into the magic circle. Merlin was a Soviet agent all right, but rather like Alleline he was also the spokesman of a dissident group. We love to see ourselves in other people's situations, and I'm sure Percy warmed to Merlin from the start. This group, this caucus of which Merlin was the leader, was made up of, say, half a dozen like-minded Soviet officials, each in his way well placed. With time, I suspect, Gerald gave his lieutenants, and Percy, a pretty close picture of these sub-sources, but I don't know. Merlin's job was to collate their intelligence and get it to the West, and over the next few months he showed remarkable versatility in doing just that. He used all manner of methods, and the Circus was only too willing to feed him the equipment. Secret writing, microdots stuck over full-stops on innocent-looking letters, dead letter boxes in Western capitals, filled by God knows what brave Russian, and dutifully cleared by Toby Esterhase's brave lamplighters. Live meetings even, arranged and watched over by Toby's babysitters' - a minute pause as Smiley glanced again towards the window - 'a couple of drops in Moscow that had to be fielded by the local residency, though they were never allowed to know their benefactor. But no clandestine radio; Merlin doesn't care for it. There was a proposal once - it even got as far as the Treasury - to set up a permanent long-arm radio station in Finland, just to service him, but it all foundered when Merlin said: "Not on your Nellie." He must have been taking lessons from Karla, mustn't he? You know how Karla hates radio. The great thing is, Merlin has mobility: that's his biggest talent. Perhaps he's in the Moscow Trade Ministry and can use the travelling salesmen. Anyway, he has the resources and he has the leads out of Russia. And that's why his fellow conspirators look to him to deal with Gerald and agree the terms, the financial terms. Because they do want money. Lots of money. I should have mentioned that. In that respect, secret services and their customers are like anyone else, I'm afraid. They value most what costs most, and Merlin costs a fortune. Ever bought a fake picture?'

'I sold a couple once,' said Toby with a flashy, nervous smile, but no one laughed.

'The more you pay for it, the less inclined you are to doubt it. Silly, but there we are. It's also comforting for everyone to know that Merlin is venal. That's a motive we all understand, right, Toby? Specially in the Treasury. Twenty thousand francs a month into a Swiss bank: well, there's no knowing who wouldn't bend a few egalitarian principles for money like that. So Whitehall pays him a fortune, and calls his intelligence priceless. And some of it is good,' Smiley conceded. 'Very good, I do think, and so it should be. Then one day, Gerald admits Percy to the greatest secret of all. The Merlin caucus has a London end. It's the start, I should tell you now, of a very, very clever knot.'

Toby put down his cup and with his handkerchief primly dabbed the corners of his mouth.

'According to Gerald, a member of the Soviet Embassy here in London is actually ready and able to act as Merlin's London representative. He is even in the extraordinary position of being able to use, on rare occasions, the Embassy facilities to talk to Merlin in Moscow, to send and receive messages. And if every imaginable precaution is taken, it is even possible now and then for Gerald to arrange clandestine meetings with this wonderman, to brief and debrief him, to put follow-up questions and receive answers from Merlin almost by return of post. We'll call this Soviet official Aleksey Aleksandrovich Polyakov, and we'll pretend he's a member of the cultural section of the Soviet Embassy. Are you with me?'

'I didn't hear anything,' said Esterhase. 'I gone deaf.'

'The story is, he's been a member of the London Embassy quite a while - nine years to be precise - but Merlin's only recently added him to the flock. While Polyakov was on leave in Moscow, perhaps?'

'I'm not hearing nothing.'

'Very quickly Polyakov becomes important, because before long Gerald appoints him linchpin of the Witchcraft operation and a lot more besides. The dead drops in Amsterdam and Paris, the secret inks, the microdots: they all go on all right, but at less of a pitch. The convenience of having Polyakov right on the doorstep is too good to miss. Some of Merlin's best material is smuggled to London by diplomatic bag: all Polyakov has to do is slit open the envelopes and pass them to his counterpart in the Circus: Gerald or whomever Gerald nominates. But we must never forget that this part of the Merlin operation is deathly, deathly secret. The Witchcraft committee itself is of course secret too, but large. That's inevitable. The operation is large, the take is large, processing and distribution alone requires a mass of clerical supervision: transcribers, translators, codists, typists, evaluators and God knows what. None of that worries Gerald at all, of course: he likes it in fact, because the art of being Gerald is to be one of a crowd. Is the Witchcraft committee led from below? From the middle or from the top? I rather like Karla's description of committees don't you? Is it Chinese? A committee is an animal with four back legs.

'But the London end - Polyakov's leg - that part is confined to the original magic circle. Skordeno, de Silsky, all the pack: they can tear off abroad and devil like mad for Merlin away from home. But here in London, the operation involving brother Polyakov, the way that knot is tied, that's a very special secret, for very special reasons. You, Percy, Bill Haydon and Roy Bland. You four are the magic circle. Right? Now let's just speculate about how it works, in detail. There's a house, we know that. All the same, meetings there are very elaborately arranged, we can be sure of that, can't we? Who meets him, Toby? Who has the handling of Polyakov? You? Roy? Bill?'

Taking the fat end of his tie, Smiley turned the silk lining outwards and began polishing his glasses. 'Everyone does,' he said, answering his own question. 'How's that? Sometimes Percy meets him. I would guess Percy represents the authoritarian side with him: "Isn't it time you took a holiday? Have you heard from your wife this week?" Percy would be good at that. But the Witchcraft committee uses Percy sparingly. Percy's the big gun and he must have rarity value. Then there's Bill Haydon; Bill meets him. That would happen more often, I think. Bill's impressive on Russia and he has entertainment value. I have a feeling that he and Polyakov would hit it off pretty well. I would think Bill shone when it came to the briefing and the follow-up questions, wouldn't you? Making certain that the right messages went to Moscow? Sometimes he takes Roy Bland with him, sometimes he sends Roy on his own. I expect that's something they work out between themselves. And Roy of course is an economic expert, as well as top man on satellites, so there'll be lots to talk about in that department also. And sometimes - I imagine birthdays, Toby, or a Christmas, or special presentations of thanks and money - there's a small fortune written down to entertainment, I notice, let alone bounties - sometimes, to make the party go, you all four trot along, and raise your glasses to the king across the water: to Merlin, through his envoy, Polyakov. Finally I suppose Toby himself has things to talk to friend Polyakov about. There's tradecraft to discuss, there are the useful snippets about goings- on inside the Embassy, which are so handy to the lamplighters in their bread-and- butter surveillance operations against the residency. So Toby also has his solo sessions. After all, we shouldn't overlook Polyakov's local potential, quite apart from his role as Merlin's London representative. It's not every day we have a tame Soviet diplomat in London eating out of our hands. A little training with a camera and Polyakov could be very useful just at the straight domestic level. Provided we all remember our priorities.'