The Hotel Islay in Sussex Gardens - where, on the day after his visit to Ascot, George Smiley under the name of Barraclough had set up his operational headquarters - was a very quiet place considering its position, and perfectly suited to his needs. It lay a hundred yards south of Paddington Station, one of a terrace of elderly mansions cut off from the main avenue by a line of plane trees and a parking patch. The traffic roared past it all night. But the inside, though it was a firebowl of clashing wallpapers and copper lampshades, was a place of extraordinary calm. Not only was there nothing going on in the hotel: there was nothing going on in the world either, and this impression was strengthened by Mrs Pope Graham, the proprietor, a major's widow with a terribly languorous voice which imparted a sense of deep fatigue to Mr Barraclough or anyone else who sought her hospitality. Inspector Mendel, whose informant she had been for many years, insisted that her name was common Graham. The Pope had been added for grandeur or out of deference to Rome.

'Your father wasn't a Greenjacket, was he, dear?' she enquired, with a yawn, as she read Barraclough in the register. Smiley paid her fifty pounds' advance for a two- week stay and she gave him room eight because he wanted to work. He asked for a desk and she gave him a rickety card table, Norman the boy brought it. 'It's Georgian,' she sighed, supervising its delivery. 'So you will love it for me, won't you, dear? I shouldn't lend it to you really, it was the major's.'

To the fifty, Mendel privately had added a further twenty on account from his own wallet, dirty oncers as he called them, which he later recovered from Smiley. 'No smell to nothing, is there?' he told her.

'You could say so,' Mrs Pope Graham agreed, demurely stowing the notes among her nether garments.

'I'll want every scrap,' Mendel warned, seated in her basement apartment over a bottle of the one she liked. 'Times of entry and exit, contacts, life-style, and most of all' - he liked an emphatic finger - 'most of all, more important than you can possibly know, this is, I'll want suspicious persons taking an interest or putting questions to your staff under a pretext.' He gave her his state-of-the- nation look. 'Even if they say they're the Guards Armoured and Sherlock Holmes rolled into one.'

'There's only me and Norman,' said Mrs Pope Graham, indicating a shivery boy in a black overcoat to which Mrs Pope Graham had stitched a velvet collar of beige. 'And they'll not get far with Norman, will they, dear, you're too sensitive.'

'Same with his incoming letters,' said the Inspector. 'I'll want postmarks and times posted where legible, but not tampering or holding back. Same with his objects.' He allowed a hush to fall as he eyed the substantial safe which formed such a feature of the furnishings. 'Now and then, he's going to ask for objects to be lodged. Mainly they'll be papers, sometimes books. There's only one person allowed to look at those objects apart from him' - he pulled a sudden, piratical grin - 'Me. Understand? No one else can even know you've got them. And don't fiddle with them or he'll know because he's sharp. It's got to be expert fiddling. I'm not saying any more,' Mendel concluded; though he did remark to Smiley, soon after returning from Somerset, that if twenty quid was all it cost them, Norman and his protectress were the cheapest babysitting service in the business.

In which boast he was pardonably mistaken, for he could hardly be expected to know of Jim's recruitment of the entire car club; nor the means by which Jim was able subsequently to trace the path of Mendel's wary investigations. Nor could Mendel, or anyone else, have guessed the state of electric alertness to which anger, and the strain of waiting, and perhaps a little madness, had seemingly brought him.

Room eight was on the top floor. Its window looked on to the parapet. Beyond the parapet lay a side street with a shady bookshop and a travel agency called the Wide World. The hand towel was embroidered 'Swan Hotel Marlow'. Lacon stalked in the same evening carrying a fat briefcase containing the first consignment of papers from his office. To talk they sat side by side on the bed while Smiley played a transistor wireless to drown the sound of their voices. Lacon took this mawkishly; he seemed somehow too old for the picnic. Next morning on his way to work Lacon reclaimed the papers and returned the books which Smiley had given him to pad out his briefcase. In this role Lacon was at his worst. His manner was offended and off-hand; he made it clear he detested the irregularity. In the cold weather, he seemed to have developed a permanent blush. But Smiley could not have read the files by day because they were on call to Lacon's staff and their absence would have caused an uproar. Nor did he want to. He knew better than anyone that he was desperately short of time. Over the next three days this procedure varied very little. Each evening on his way to take the train from Paddington, Lacon dropped in his papers and each night Mrs Pope Graham furtively reported to Mendel that the sour gangly one had called again, the one who looked down his nose at Norman. Each morning, after three hours' sleep and a disgusting breakfast of undercooked sausage and overcooked tomato - there was no other menu - Smiley waited for Lacon to arrive, then slipped gratefully into the cold winter's day to take his place among his fellow men.

They were extraordinary nights for Smiley alone up there on the top floor. Thinking of them afterwards, though his days between were just as fraught and on the surface more eventful, he recalled them as a single journey, almost a single night. 'And you'll do it?' Lacon had piped shamelessly in the garden. 'Go forwards, go backwards?' As Smiley retraced path after path into his own past, there was no longer any difference between the two: forwards or backwards, it was the same journey and its destination lay ahead of him. There was nothing in that room, no object among that whole magpie collection of tattered hotel junk, that separated him from the rooms of his recollection. He was back on the top floor of the Circus, in his own plain office with the Oxford prints, just as he had left it a year ago. Beyond his door lay the low-ceilinged anteroom where Control's grey-haired ladies, the mothers, softly typed and answered telephones; while here in the hotel an undiscovered genius along the corridor night and day tapped patiently at an old machine. At the anteroom's far end - in Mrs Pope Graham's world there was a bathroom there, and a warning not to use it - stood the blank door that led to Control's sanctuary: an alley of a place, with old steel cupboards and old red books, a smell of sweet dust and jasmine tea. Behind the desk, Control himself, a carcass of a man by then, with his lank grey forelock and his smile as warm as a skull.

This mental transposition was so complete in Smiley that when his phone rang - the extension was an extra, payable in cash - he had to give himself time to remember where he was. Other sounds had an equally confusing effect on him, such as the rustle of pigeons on the parapet, the scraping of the television mast in the wind, and in rain the sudden river gurgling in the roof valley. For these sounds also belonged to his past, and in Cambridge Circus were heard by the fifth floor only. His ear selected them no doubt for that very reason: they were the background jingle of his past. Once in the early morning, hearing a footfall in the corridor outside his room, Smiley actually went to the bedroom door expecting to let in the Circus night coding clerk. He was immersed in Guillam's photographs at the time, puzzling out from far too little information the likely Circus procedure under lateralism for handling an incoming telegram from Hong Kong. But instead of the clerk he found Norman barefooted in pyjamas. Confetti was strewn over the carpet and two pairs of shoes stood outside the opposite door, a man's and a girl's, though no one at the Islay, least of all Norman, would ever clean them.

'Stop prying and go to bed,' said Smiley. And when Norman only stared: 'Oh do go away, will you?' - And nearly, but he stopped himself in time - 'you grubby little man.'

'Operation Witchcraft,' read the title on the first volume which Lacon had brought to him that first night. 'Policy regarding distribution of Special Product.' The rest of the cover was obliterated by warning labels and handling instructions, including one which quaintly advised the accidental finder to 'return the file unread' to the Chief Registrar at the Cabinet Office. 'Operation Witchcraft,' read the second. 'Supplementary estimates to the Treasury, special accommodation in London, special financing arrangements, bounty etc.' 'Source Merlin,' read the third, bound to the first with pink ribbon. 'Customer Evaluations, cost effectiveness, wider exploitation, see also Secret Annexe.' But the secret annexe was not attached, and when Smiley asked for it there was a coldness.

'The Minister keeps it in his personal safe,' Lacon snapped.

'Do you know the combination?'

'Certainly not,' he retorted, now furious.

'What is the title of it?'

'It can be of no possible concern to you. I entirely fail to see why you should waste your time chasing after this material in the first place. It's highly secret and we have done everything humanly possible to keep the readership to the minimum.'

'Even a secret annexe has to have a title,' said Smiley mildly.

'This has none.'

'Does it give the identity of Merlin?'

'Don't be ridiculous. The Minister would not want to know, and Alleline would not want to tell him.'

'What does wider exploitation mean?'

'I refuse to be interrogated, George. You're not family any more, you know. By rights I should have you specially cleared as it is.'

'Witchcraft-cleared?'

'Yes.'

'Do we have a list of people who have been cleared in that way?'

It was in the policy file, Lacon retorted, and all but slammed the door on him before coming back, to the slow chant of 'Where have all the flowers gone?' introduced by an Australian disc-jockey. 'The Minister-' He began again. 'He doesn't like devious explanations. He has a saying: he'll only believe what can be written on a postcard. He's very impatient to be given something he can get his hands on.'

Smiley said: 'You won't forget Prideaux, will you? Just anything you have on him at all; even scraps are better than nothing.'

With that Smiley left Lacon to glare a while, then make a second exit: 'You're not going fey are you, George? You realise that Prideaux had most likely never even heard of Witchcraft before he was shot? I really do fail to see why you can't stick with the primary problem instead of rootling around in...' But by this time he had talked himself out of the room.