Enigma

1

CAMBRIDGE IN THE fourth winter of the war: a ghost town.

A ceaseless Siberian wind with nothing to blunt its edge for a thousand miles whipped off the North Sea and swept low across the Fens. It rattled the signs to the air-raid shelters in Trinity New Court and battered on the boarded-up windows of King's College Chapel. It prowled through the quadrangles and staircases, confining the few dons and students still in residence to their rooms. By mid-afternoon the narrow cobbled streets were deserted. By nightfall, with not a light to be seen, the university was returned to a darkness it hadn't known since the Middle Ages. A procession of monks shuffling over Magdalene Bridge on their way to Vespers would scarcely have seemed out of place.

In the wartime blackout the centuries had dissolved.

It was to this bleak spot in the flatlands of eastern England that there came, in the middle of February 1943, a young mathematician named Thomas Jericho. The authorities of his college, King's, were given less than a day's notice of his arrival – scarcely enough time to reopen his rooms, put sheets on his bed, and have more than three years' worth of dust swept from his shelves and carpets. And they would not have gone to even that much trouble, it being wartime and servants so scarce – had not the Provost himself been telephoned at the Master's Lodge by an obscure but very senior official of His Majesty's Foreign Office, with a request that 'Mr Jericho be looked after until he is well enough to return to his duties'.

'Of course,' replied the Provost, who couldn't for the life of him put a face to the name of Jericho. 'Of course. A pleasure to welcome him back.'

As he spoke, he opened the college register and flicked through it until he came to: Jericho, T. R. G.; matriculated, 1935; Senior Wrangler, Mathematics Tripos, 1938; Junior Research Fellow at two hundred pounds a year; not seen in the university since the outbreak of war.

Jericho? Jericho? To the Provost he was at best a dim memory, a fuzzy adolescent blob on a college photograph. Once, perhaps, he would have remembered the name, but the war had shattered the sonorous rhythm of intake and graduation and all was chaos – the Pitt Club was a British Restaurant, potatoes and onions were growing in the gardens of St John's…

'He has recently been engaged upon work of the gravest national importance,' continued the caller. 'We would appreciate it if he were not disturbed.'

'Understood,' said the Provost. 'Understood. I shall see to it he is left alone.'

'We are obliged to you.'

The official rang off. 'Work of the gravest national importance', by God… The old man knew what that meant. He hung up and looked thoughtfully at the receiver for a few moments, then went in search of the domestic bursar.

A Cambridge college is a. village, with a village's appetite for gossip – all the keener when that village is nine-tenths empty – and the return of Jericho provoked hours of analysis among the college staff.

There was, for a start, the manner of his arrival – a few hours after the call to the Provost, late on a snowy night, swaddled in a travelling rug, in the back of a cavernous official Rover driven by a young chauffeuse in the dark blue uniform of the Women's Royal Navy. Kite, the porter, who offered to carry the visitor's bags to his rooms, reported that Jericho clung to his pair of battered leather suitcases and refused to let go of either, even though he looked so pale and worn out that Kite doubted he would make it up the spiral staircase unaided.

Dorothy Saxmundham, the bedder, saw him next, when she went in the following day to tidy up. He was propped on his pillows staring out at the sleet pattering across the river, and he never turned his head, never even looked at her, didn't seem to know she was there, poor lamb. Then she went to move one of his cases and he was up in a flash – 'Please don't touch that, thank you so much, Mrs Sax, thank you' – and she was out on the landing in a quarter of a minute.

He had only one visitor: the college doctor, who saw him twice, stayed for about fifteen minutes on each occasion, and left without saying a word.

He took all his meals in his room for the first week – not that he ate very much, according to Oliver Bickerdyke, who worked in the kitchens: he took up a tray three times a day, only to take it away again an hour later, barely touched. Bickerdyke's great coup, which led to at least an hour of speculation around the coke stove in the Porter's Lodge, was to come upon the young man working at his desk, wearing a coat over his pyjamas, a scarf and a pair of mittens. Normally, Jericho 'sported his oak' – that is to say, he kept the heavy outer door to his study firmly shut – and called politely for his tray to be left outside. But on this particular morning, six days after his dramatic arrival, he had left it slightly ajar. Bickerdyke deliberately brushed the wood lightly with his knuckles, so quietly as to be inaudible to any living creature, save possibly a grazing gazelle, and then he was across the threshold and within a yard of his quarry before Jericho turned round. Bickerdyke just had time to register piles of papers ('covered in figures and circuits and Greek and suchlike') before the work was hastily covered up and he was sent on his way. Thereafter the door remained locked.

Listening to Bickerdyke's tale the next afternoon, and not wishing to be outdone, Dorothy Saxmundham added a detail of her own. Mr Jericho had a small gas fire in his sitting room and a grate in his bedroom. In the grate, which she had cleaned that morning, he had obviously burned a quantity of paper.

There was silence while this intelligence was digested.

'Could be The Times,' said Kite eventually. 'I puts a copy of The Times under his door every morning.'

No, declared Mrs Sax. It was not The Times. They were still in a pile by the bed. 'He doesn't seem to read them, not as I've noticed. He just does the crosswords.'

Bickerdyke suggested he was burning letters. 'Maybe love letters,' he added, with a leer.

'Love letters? Him? Get away.' Kite took off his antique bowler hat, inspected its frayed brim, then replaced it carefully on his bald head. 'Besides, he ain't had any letters, not a single one, not since he's been here.'

And so they were forced to the conclusion that what Jericho was burning in his grate was his work – work so secret, nobody could be allowed to see even a fragment of the waste. In the absence of hard fact, fantasy was piled upon fantasy. He was a government scientist, they decided. No, he worked in Intelligence. No, no -he was a genius. He had had a nervous breakdown. His presence in Cambridge was an official secret. He had friends in high places. He had met Mr Churchill. He had met the King…

In all of which speculation, they would have been gratified to learn, they were absolutely and precisely correct.

Three days later, early on the morning of Friday 26 February, the mystery was given a fresh twist.

Kite was sorting the first delivery of mail, stuffing a small sackful of letters into the few pigeon holes whose owners were still in college, when he came across not one but three envelopes addressed to T. R. G. Jericho Esq, originally sent care of the White Hart Inn, Shenley Church End, Buckinghamshire, and subsequently forwarded to King's. For a moment, Kite was taken aback. Did the strange young man, for whom they had constructed such an exotic identity, in reality manage a pub? He pushed his spectacles up on to his forehead, held the envelope at arm's length, and squinted at the postmarks.

Bletchley.

There was an old Ordnance Survey map hanging at the back of the lodge, showing the dense triangle of southern England enclosed by Cambridge, Oxford and London. Bletchley sat astride a big railway junction exactly midway between the two university towns. Shenley Church End was a tiny hamlet about four miles north-west of it.

Kite studied the more interesting of the three envelopes. He raised it to his bulbous, blue-veined nose. He sniffed it. He had been sorting mail for more than forty years and he knew a woman's handwriting when he saw it: clearer and neater, more looped and less angular than a man's. A kettle was boiling on the gas ring at the back of the stove. He glanced around. It was not yet eight, and barely light outside. Within seconds he had stepped into the alcove and was holding the flap of the envelope to the steam. It was made of thin, shoddy wartime paper, sealed with cheap glue. The flap quickly moistened, curled, opened, and Kite extracted a card.

He had just about read through to the end when he heard the lodge door open. A blast of wind shook the windows. He stuffed the card back into the envelope, dipped his little finger into the glue pot kept ready by the stove, stuck down the flap, then casually poked his head round the corner to see who had come in. He almost had a stroke.

'Good heavens – morning – Mr Jericho – sir…'

'Are there any letters for me, Mr Kite?' Jericho's voice was firm enough, but he seemed to sway slightly and held on to the counter like a sailor who had just stepped ashore after a long voyage. He was a pale young man, quite short, with dark hair and dark eyes – twin darknesses that served to emphasise the pallor of his skin.

'Not as I've noticed, sir. I'll look again.'

Kite retreated with dignity to the alcove and tried to iron out the damp envelope with his sleeve. It was only slightly crumpled. He slipped it into the middle of a handful of letters, came out to the front, and performed – even if he said so himself – a virtuoso pantomime of searching through them.:

'No, no, nothing, no. Ah, yes, here's, something. Gracious. And two more.' Kite proffered them across the counter. 'Your birthday, sir?'

'Yesterday.' Jericho stuffed the envelopes into the inside pocket of his overcoat without glancing at them.

'Many happy returns, sir.' Kite watched the letters disappear and gave a silent sigh of relief. He folded his arms and leaned forward on the counter. 'Might I hazard a guess at your age, sir? Came up in 'thirty-five, as I recall. Would that make you, perhaps, twenty-six?'

'I say, is that my newspaper, Mr Kite? Perhaps I might take it. Save you the trouble.'

Kite grunted, pushed himself back up on his feet and fetched it. He made one last attempt at conversation as he handed it over, remarking on the satisfactory progress of the war in Russia since Stalingrad and Hitler being finished if you asked him -but, of course, that he, Jericho, would surely be more up to date about such matters than he, Kite…? The younger man merely smiled.

'I doubt if my knowledge about anything is as up to date as yours, Mr Kite, not even about myself. Knowing your methods.'

For a moment, Kite was not sure he had heard correctly. He stared sharply at Jericho, who met his gaze and held it with his dark brown eyes, which seemed suddenly to have acquired a glint of life. Then, still smiling, Jericho nodded 'Good morning', tucked his paper under his arm and was gone. Kite watched him through the lodge's mullioned window – a slender figure in a college scarf of purple and white, unsteady on his feet, head bowed into the wind. 'My methods,' he repeated to himself. 'My methods?'

That afternoon, when the trio gathered for tea as usual around the coke stove, he was able to advance a whole new explanation for Jericho's presence in their midst. Naturally, he could not disclose how he came by his information, only that it was especially reliable (he hinted at a man-to-man chat). Forgetting his earlier scorn about love letters, Kite now asserted with confidence that the young fellow was obviously suffering from a broken heart.

2

Jericho did not open his letters immediately. Instead he squared his shoulders and tilted forwards into the wind. After a week in his room, the richness of the oxygen pummelling his face made him feel lightheaded. He turned right at the Junior Combination Room and followed the flagstone path that led through the college and over the little hump-back bridge to the water meadow beyond. To his left was the college hall, to his right, across a great expanse of lawn, the massive cliff-face of the chapel. A tiny column of choirboys was bobbing through its grey lee, gowns flapping in the gale.

He stopped, and a gust of wind rocked him on his heels, forcing him half a step backwards. A stone passageway led off from one side of the path, its arch grown over with untended ivy. He glanced, by force of habit, at the set of windows on the second floor. They were dark and shuttered. Here, too, the ivy had been allowed to grow unchecked, so that several of the small, diamond-shaped panes were lost behind thick foliage.

He hesitated, then stepped off the path, under the keystone, into the shadows.

The staircase was just as he remembered it, except that now this wing of the college was closed and the wind had blown dead leaves into the well of the steps. An old newspaper curled itself around his legs like a hungry cat. He tried the light switch. It clicked uselessly. There was no bulb. But he could still make out the name, one of three painted on a wooden board in elegant white capitals, now cracked and faded.

TURING, A.M.

How nervously he had climbed these stairs for the first time – when? in the summer of 1938? a world ago – to find a man barely five years older than himself, as shy as a freshman, with a hank of dark hair falling across his eyes: the great Alan Turing, the author of On Computable Numbers, the progenitor of the Universal Computing Machine…

Turing had asked him what he proposed to take as his subject for his first year's research.

'Riemann's theory of prime numbers.'

'But I am researching Riemann myself.'

'I know,' Jericho had blurted out, 'that's why I chose it.'

And Turing had laughed at this outrageous display of hero worship, and had agreed to supervise Jericho's research, even though he hated teaching.

Now Jericho stood on the landing and tried Turing's door. Locked, of course. The dust smeared his hand. He tried to remember how the room had looked. Squalor had been the overwhelming impression. Books, notes, letters, dirty clothes, empty bottles and tins of food had been strewn across the floor. There had been a teddy bear called Porgy on the mantelpiece above the gas fire, and a battered violin leaning in the corner, which Turing had picked up in a junk shop.

Turing had been too shy a man to get to know well. In any case, from the Christmas of 1938 he was hardly ever to be seen. He would cancel supervisions at the last minute saying he had to be in London. Or Jericho would climb these stairs and knock and there would be no reply, even though Jericho could sense he was behind the door. When, at last, around Easter 1939, not long after the Nazis had marched into Prague, the two men had finally met, Jericho had nerved himself to say: 'Look, sir, if you don't want to supervise me…'

'It's not that.'

'Or if you're making progress on the Riemann Hypothesis and you don't want to share it…"

Turing had smiled. 'Tom, I can assure you I am making no progress on Riemann whatsoever.'

Then what…?'

'It's not Riemann.' And then he had added, very quietly: 'There are other things now happening in the world, you know, apart from mathematics…'

Two days later Jericho had found a note in his pigeonhole.

'Please join me for a glass of sherry in my rooms this evening. F.J. Atwood.'

Jericho turned from Turing's room. He felt faint. He gripped the worn handrail, taking each step carefully, like an old man.

Atwood. Nobody refused an invitation from Atwood, professor of ancient history, dean of the college before Jericho was even born, a man with a spider's web of connections in Whitehall. It was tantamount to a summons from God.

'Speak any languages?' had been Atwood's opening question as he poured the drinks. He was in his fifties, a bachelor, married to the college. His books were arranged prominently on the shelf behind him. The Greek and Macedonian Art of War. Caesar as Man of Letters. Thucydides and His History.

'Only German.' Jericho had learned it in adolescence to read the great nineteenth-century mathematicians – Gauss, Kummer, Hilbert.

Atwood had nodded and handed over a tiny measure of very dry sherry in a crystal glass. He followed Jericho's gaze to the books. 'Do you know Herodotus, by any chance? Do you know the story of Histiaeus?'

It was a rhetorical question; Atwood's questions mostly were.

'Histiaeus wished to send a message from the Persian court to his son-in-law, the tyrant Aristagoras, at Miletus, urging him to rise in revolt. However, he feared any such communication would he intercepted. His solution was to shave the head of his most trusted slave, tattoo the message onto his naked scalp, wait for his hair to grow, then send him to Aristagoras with a request that he be given a haircut. Unreliable but, in his case, effective. Your health.'

Jericho learned later that Atwood told the same stories to all his recruits. Histiaeus and his bald slave gave way to Polybius and his cipher square, then came Caesar's letter to Cicero using an alphabet in which a was enciphered as d, b as e, c as f, and so forth. Finally, still circling the subject, but closer now, had come the lesson in etymology.

'The Latin crypta, from the Greek root kpvTTpt? meaning "hidden, concealed". Hence crypt, burial place of the dead, and crypto, secret. Crypto-communist, crypto-fascist… By the way, you're not either, are you?'

'I'm not a burial place of the dead, no.'

' Cryptogram…' Atwood had raised his sherry to the light and squinted at the pale liquid. 'Cryptanalysis…Turing tells me he thinks you might be rather good…'

Jericho was running a fever by the time he reached his rooms. He locked the door and flopped face down on his unmade bed, still wearing his coat and scarf. Presently he heard footsteps and someone knocked.

'Breakfast, sir.'

'Just leave it outside. Thank you.'

'Are you all right, sir?'

'I'm fine.'

He heard the clatter of the tray being set down, and steps retreating. The room seemed to be lurching and swelling out of all proportion, a corner of the ceiling was suddenly huge and close enough to touch. He closed his eyes and the visions came up at him through the darkness -

– Turing, smiling his shy half smile: 'Tom, I can assure you, I am making no progress on Riemann whatsoever…'

– Logie, pumping his hand in the Bombe Hut, shouting above the noise of the machinery, 'The Prime Minister has just been on the telephone with his congratulations…"

– Claire, touching his cheek, whispering, 'Poor you, I've really got under your skin, haven't I, poor you…'

– 'Stand back' – a man's voice, Logie's voice – 'Stand back, give him air…'

And then there was nothing.

When he woke, the first thing he did was look at his watch. He'd been unconscious for about an hour. He sat up and patted his overcoat pockets. Somewhere he had a notebook in which he recorded the duration of each attack, and the symptoms. It was a distressingly long list. He found instead the three envelopes.

He laid them out on the bed and considered them for a while. Then he opened two of them. One was a card from his mother, the other from his aunt, both wishing a happy birthday. Neither woman had any idea what he was doing and both, he knew, were guiltily disappointed he wasn't in uniform and being shot at, like the sons of most of their friends.

'But what do I tell people?' his mother had asked him in despair during one of his brief visits home, after he had refused yet again to tell her what he did.

'Tell them I'm in government communications,' he had replied, using the formula they had been instructed to deploy in the face of persistent enquiries.

'But perhaps they'd like to know a little more than that.'

'Then they're acting suspiciously and you should call the police.'

His mother had contemplated the social catastrophe of her bridge four being interviewed by the local inspector, and had fallen silent.

And the third letter? Like Kite before him, he turned it over and sniffed it. Was it his imagination or was there a trace of scent? Ashes of Roses by Bourjois, a minuscule bottle of which had practically bankrupted him just a month earlier. He used his slide rule as a paperknife and slit the envelope open. Inside was a cheap card, carelessly chosen – it showed a bowl of fruit, of all things – and a standard message for the circumstances, or so he guessed, never having been in this situation before. 'Dearest T… always see you as a friend… perhaps in the future… sorry to hear about… in haste… much love…' He closed his eyes.

Later, after he had filled in the crossword, after Mrs Sax had finished the cleaning, after Bickerdyke had deposited another tray of food and taken it away again untouched, Jericho got down on his hands and knees and tugged a suitcase from beneath his bed and unlocked it. Folded into the middle of his 1930 Doubleday first edition of The Complete Sherlock Holmes were six sheets of foolscap covered in his tiny writing. He took them over to the rickety desk beside the window and smoothed them out.

'The cipher machine converts the input(plain language, P) into the cipher (Z) by means of a function f. Thus Z=f(P,K) where K denotes the key…"

He sharpened his pencil, blew away the shavings and bent over the sheets.

'Suppose K has N possible values. For each of the N assumptions we must see if f(Z,K) produces plain language, where f'1 is the deciphering function which produces P if K is correct

The wind ruffled the surface of the Cam. A flotilla of ducks rode the waves, without moving, like ships at anchor. He put down his pencil and read her card again, trying to measure the emotion, the meaning behind the flat phrases. Could one, he wondered, construct a similar formula for letters – for love letters or for letters signalling the end of love?

'The input (sentiment, S) is converted into a message (M) by the woman, by means of the Junction w. Thus M=w(S,V) where V denotes the vocabulary. Suppose V has N possible values…'

The mathematical symbols blurred before his eyes. He took the card into the bedroom, to the grate, knelt and struck a match. The paper flared briefly and twisted in his hand, then swiftly turned to ash.

Gradually his days acquired a shape.

He would rise early and work for two or three hours. Not at cryptanalysis – he burned all that on the day he burned her card – but at pure mathematics. Then he would take a nap. He would fill in The Times crossword before lunch, timing himself on his father's old pocket watch – it never took him more than five minutes to complete it, and once he finished it in three minutes forty. He managed to solve a series of complex chess problems – 'the hymn tunes of mathematics', as G.H. Hardy called them – without using pieces or a board. All this reassured him his brain had not been permanently impaired.

After the crossword and the chess he would skim through the war news while trying to eat something at his desk. He tried to avoid the Battle of the Atlantic (DEAD MEN AT THE OARS: U-BOAT VICTIMS FROZEN IN LIFEBOATS) and concentrated instead on the Russian Front: Pavlograd, Demiansk, Rzhev… the Soviets seemed to recapture a new town every few hours and he was amused to find The Times reporting Red Army Day as respectfully as if it were the King's Birthday.

In the afternoon he would walk, a little further on each occasion – at first confining himself to the college grounds, then strolling through the empty town, and finally venturing into the frozen countryside – before returning as the light faded to sit by the gas fire and read his Sherlock Holmes. He began to go into Hall for dinner, although he declined politely the Provost's offer of a place at High Table. The food was as bad as at Bletchley, but the surroundings were better, the candlelight flickering on the heavy-framed portraits and gleaming on the long tables of polished oak. He learned to ignore the frankly curious stares of the college staff. Attempts at conversation he cut off with a nod. He didn't mind being solitary. Solitude had been his life. An only child, a stepchild, a 'gifted' child -always there had been something to set him apart. At one time he couldn't speak about his work because hardly anyone would understand him. Now he couldn't speak of it because it was classified. It was all the same.

By the end of his second week he had actually started to sleep through the night, a feat he hadn't managed for more than two years.

Shark, Enigma, kiss, bombe, break, pinch, drop, crib – all the weird vocabulary of his secret life he slowly succeeded in erasing from his conscious mind. To his astonishment, even Claire's image became diffuse. There were still vivid flashes of memory, especially at night – the lemony smell of newly washed hair, the wide grey eyes as pale as water, the soft voice half amused, half bored – but increasingly the parts failed to cohere. The whole was vanishing.

He wrote to his mother and persuaded her not to visit him.

'Nurse Time,' the doctor had said, snapping shut his bag of tricks, 'that's who'll cure you. Mr Jericho. Nurse Time.'

Rather to Jericho's surprise it seemed that the old boy was right. He was going to be well again. 'Nervous exhaustion' or whatever they called it was not the same as madness after all.

And then, without warning, on Friday 12 March, they came for him.

The night before it happened he had overheard an elderly don complaining about a new air base the Americans were building to the east of the city.

'I said to them, you do realise you're standing on a fossil site of the Pleistocene era? That I myself have removed from here the horncores of Bos primigenius? D'you know, the fellow merely laughed…'

Good for the Yanks, thought Jericho, and he decided there and then it would make a suitable destination for his afternoon walk. Because it would take him at least three miles further than he had attempted so far, he left earlier than usual, straight after lunch.

He strode briskly along the Backs, past the Wren Library and the icing sugar towers of St John's, past the sports field in which two dozen little boys in purple shirts were playing football, and then turned left, trudging beside the Madingley Road. After ten minutes he was in open country.

Kite had gloomily predicted snow, but although it was still cold it was sunny and the sky was a glory – a pure blue dome above the flat landscape of East Anglia, filled for miles with the silver specks of aircraft and the white scratches of contrails. Before the war he had cycled through this quiet countryside almost every week and had barely seen a car. Now an endless succession of big American trucks lumbered past him, forcing him on to the verge – brasher, faster, more modern than British Army lorries, covered over at the back with camouflaged tarpaulins. The white faces of the US airmen peered out of the shadows. Sometimes the men shouted and waved and he waved back, feeling absurdly English and self-conscious.

Eventually he came within sight of the new base and stood beside the road watching three Flying Fortresses take off in the distance, one after the other – vast aircraft, almost too heavy, or so it seemed to Jericho, to escape the ground. They lumbered along the fresh concrete runway, roaring with frustration, clawing at the air for liberation until suddenly a crack of daylight appeared beneath them, and the crack widened, and they were aloft.

He stood there for almost half an hour, feeling the air pulse with the vibrations of their engines, smelling the faint scent of aviation spirit carried on the cold air. He had never seen such a demonstration of power. The fossils of the Pleistocene era, he reflected with grim delight, must now be so much dust. What was that line of Cicero that Atwood was so fond of quoting? 'Nervos belli, pecuniam infinitam.' The sinews of war, unlimited money.

He looked at his watch and realised he had better turn back if he was going to reach the college before dark.

He had gone about a mile when he heard an engine behind him. A jeep overtook him, swerved and stopped. The driver, wrapped in a heavy overcoat, stood up and beckoned to him.

'Hey, fella! Wanna lift?'

'That would be kind. Thank you.'

'Jump in.'

The American didn't want to talk, which suited Jericho. He gripped the edges of his seat and stared ahead as they bounced and rattled at speed down the darkening lanes and into the town. The driver dropped him at the back of the college, waved, gunned the engine, and was gone. Jericho watched him disappear, then turned and walked through the gate.

Before the war, this three-hundred-yard walk, at this time of day, at this time of year, had been Jericho's favourite: the footpath running across a carpet of mauve and yellow crocuses, the worn stones lit by ornate Victorian lamps, the spires of the chapel to the left, the lights of the college to the right. But the crocuses were late, the lanterns had not been switched on since 1939, and a static water tank disfigured the famous aspect of the chapel. Only one light gleamed faintly in the college and as he walked towards it he gradually realised it was his window.

He stopped, frowning. Had he left his desk light on? He was sure he hadn't. As he watched, he saw a shadow, a movement, a figure in the pale yellow square. Two seconds later the light went on in his bedroom.

It wasn't possible, was it?

He started to run. He covered the distance to his staircase in thirty seconds and took the steps like an athlete. His boots clattered on the worn stone. 'Claire?' he shouted. 'Claire?' On the landing his door stood open.

'Steady on, old thing,' said a male voice from within, 'you'll do yourself a mischief.'

3

Guy Logie was a tall, cadaverous man, ten years older than Jericho. He lay on his back on the sofa facing the door, his neck on one armrest, his bony ankle dangling over the other, long hands folded neatly on his stomach. A pipe was clamped between his teeth and he was blowing smoke rings at the ceiling. Distended haloes drifted upwards, twisted, broke and melted into haze. He took his pipe from his mouth and gave an elaborate yawn which seemed to take him by surprise.

'Oh, God. Sorry.' He opened his eyes and swung himself into a sitting position. 'Hello, Tom.'

'Oh please. Please, don't get up,' said Jericho. 'Please, I insist, make yourself at home. Perhaps I could get you some tea?'

'Tea. What a grand idea.' Before the war Logie had been head of mathematics at a vast and ancient public school. He had a Blue in rugger and another in hockey and irony bounced off him like pebbles off an advancing rhinoceros. He crossed the room and grasped Jericho by the shoulders. 'Come here. Let me look at you, old thing,' he said, turning him this way and that towards the light. 'Oh dear oh dear, you do look bloody terrible.'

Jericho shrugged himself free. 'I was fine.'

'Sorry. We did knock. Your porter chap let us in.'

'Us?'

There was a noise from the bedroom.

'We came in the car with the flag on it. Greatly impressed your Mr Kite.' Logie followed Jericho's gaze to the bedroom door. 'Oh, that? That's Leveret! Don't mind him.' He took out his pipe and called: 'Mr Leveret! Come and meet Mr Jericho. The famous Mr Jericho.'

A small man with a thin face appeared at the entrance to the bedroom.

'Good afternoon, sir.' Leveret wore a raincoat and trilby. His voice had a slight northern accent.

'What the hell are you doing in there?'

'He's just checking you're alone,' said Logie sweetly.

'Of course I'm bloody well alone!'

'And is the whole staircase empty, sir?' enquired Leveret. 'Nobody in the rooms above or below?'

Jericho threw up his hands in exasperation. 'Guy, for God's sake!'

'I think it's all clear,' said Leveret to Logie. 'I've already closed the blackout curtain in there.' He turned to Jericho. 'Mind if I do the same here, sir?' He didn't wait for permission. He crossed to the small leaded window, opened it, took off his hat and thrust his head out, peering up and down, left and right. A freezing mist was off the river and a blast of chill air filled the room. Satisfied, Leveret ducked back inside, closed the window and drew the curtains.

There was a quarter of a minute's silence. Logie broke it by rubbing his hands and saying: 'Any chance of a fire, Tom? I'd forgotten what this place was like in winter. Worse than school. And tea? You mentioned tea? Would you like some tea, Mr Leveret?'

'I would indeed, sir.'

'And what about some toast? I noticed you had some bread, Tom, in the kitchen over there. Toast in front of a college fire? Wouldn't that take us back?'

Jericho looked at him for a moment. He opened his mouth to protest then changed his mind. He took a box of matches from the mantelpiece, struck a light and held it to the gas fire. As usual the pressure was low and the match went out. He lit another and this time it caught. A worm of flame glowed blue and began to spread. He went across the landing to the little kitchen, filled the kettle and lit the gas ring. In the bread bin there was indeed a loaf- Mrs Saxmundham must have put it there earlier in the week – and he sawed off three grey slices. In the cupboard he found a pre-war pot of jam, surprisingly presentable after he had scraped the white fur of mould from its surface, and a smear of: margarine on a chipped plate. He arranged his delicacies on a tray and stared at the kettle.

Perhaps he was having a dream? But when he looked back into his sitting room, there was Logie stretched out again on the sofa, and Leveret perched uneasily on the edge of one of the chairs, his hat in his hands, like an unreliable witness waiting to go into court with an under-rehearsed story.

Of course they had brought bad news. What else ' could it be but bad news? The acting head of Hut 8 wouldn't travel fifty miles across country in the deputy director's precious bloody car just to pay a social call. They were going to sack him. 'Sorry, old thing, but we can't carry passengers…' Jericho felt suddenly very tired. He massaged his forehead with the heel of his hand. The familiar headache was beginning to return, spreading up from his sinuses to the back of his eyes.

He had thought it was her. That was the joke. For about half a minute, running towards the lighted window, he had been happy. It was pitiful.

The kettle was beginning to boil. He prised open the tea caddy to find age had reduced the tea leaves to dust.

Nevertheless he spooned them into the pot and tipped in the hot water.

Logie pronounced it nectar.

Afterwards they sat in silence in the semi-darkness. The only illumination was provided by the faint gleam of the desk lamp behind them and the blue glow of the fire at their feet. The gas jet hissed. From beyond the blackout curtains came a faint flurry of splashes and the mournful quacking of a duck. Logie sat on the floor, his long legs outstretched, fiddling with his pipe. Jericho slouched in one of the two easy chairs, prodding the carpet absent-mindedly with the toasting fork. Leveret had been told to stand guard outside: 'Would you mind closing both doors, old thing? The inner door and the outer door, if you'd be so kind?'

The warm aroma of toast hung over the room. Their plates had been pushed to one side.

'This really is most companionable,' murmured Logie. He struck a match and the objects on the mantelpiece threw brief shadows on the damp wall. 'Although one appreciates that one is, in a sense, fortunate to be in a place like Bletchley, given where else one might be, one does start to get rather down with the sheer drabness of it all. Don't you find?'

'I suppose so.' Oh, do get on with it, thought Jericho, stabbing at a couple of crumbs. Just sack me and leave. Logie made a contented sucking noise through his pipe, then said quietly: 'You know, we've all been terribly worried about you, Tom. I do hope you haven't felt abandoned.'

At this unexpected display of concern, Jericho was surprised and humiliated to find tears pricking at his eyes. He kept looking down at the carpet. 'I'm afraid I made the most frightful ass of myself, Guy. The worst of it is, I can't remember much of what happened. There's almost a week that's pretty well a blank.'

Logie gave a dismissive wave of his pipe. 'You're not the first to bust his health in that place, old thing. Did you see in The Times poor Dilly Knox died last week? They gave him a gong at the end. Nothing too fancy – CMG, I think. Insisted on receiving it at home, personally, propped up in his chair. Dead two days later. Cancer. Ghastly. And then there was Jeffreys. Remember him?'

'He was sent back to Cambridge to recover as well.'

'That's the man. Whatever happened to Jeffreys?'

'He died.'

'Ah. Shame.' Logie performed a bit more pipe smoker's business, tamping down the tobacco and striking another match.

Just don't let them put me in admin, prayed Jericho. Or Welfare. There was a man in Welfare, Claire had told him, in charge of billeting, who made the girls sit on his knee if they wanted digs with a bathroom.

'It was Shark, wasn't it,' said Logie, giving him a shrewd look through a cloud of smoke, 'that did for you?'

'Yes. Perhaps. You could say that.' Shark nearly did for all of us, thought Jericho. 'But you broke it,' pursued Logie. 'You broke Shark.'

'I wouldn't put it quite like that. We broke it.'

'No. You broke it.' Logie twirled the spent match in his long finger. 'You broke it. And then it broke you.'

Jericho had a sudden memory-flash of himself on a bicycle, under a starlit sky. A cold night and the cracking of ice.

'Look,' he said, suddenly irritated 'd'you think we could get to the point here, Guy? I mean, tea in front of the college fire talking about old times? It's all very pleasant, but come on -'

'This is the point, old thing.' Logie drew his knees up under his chin and wrapped his hands around his shins. 'Shark, Limpet, Dolphin, Oyster, Porpoise, Winkle. The six little fishes in our aquarium, the six German naval Enigmas. And the greatest of these is Shark.' He stared into the fire and for the first time Jericho was able to have a good look at his face, ghostly in the blue light, like a skull. The eye sockets were hollows of darkness. He looked like a man who hadn't slept for a week. He yawned again. 'You know, I was trying to remember, in the car coming over, who decided to call it Shark in the first place.'

'I can't recall,' said Jericho. 'I've an idea it was Alan. Or maybe it was me. Anyway, what the devil does it matter? It just emerged. Nobody argued. Shark was the perfect name for it. We could tell at once it was going to be a monster.'

'And it was.' Logie puffed on his pipe. He was starting to disappear in a bank of fumes. The cheap wartime tobacco smelled like burning hay. 'And it is.'

Something in the way he delivered that last word – some slight hesitation – made Jericho look up sharply.

The Germans called it Triton, after the son of Poseidon, the demigod of the ocean who blew through, a twisted seashell to raise the furies of the deep. 'German humour,' Puck had groaned when they discovered the code name, 'German fucking humour But at Bletchley they stuck to Shark. It was a tradition, and they were British and they liked their traditions. They named all the enemy's ciphers after sea creatures. The main German naval cipher they called Dolphin. Porpoise was the Enigma key for Mediterranean surface vessels and shipping in the Black Sea. Oyster was an 'officer only' variation on Dolphin. Winkle was the 'officer only' variant of Porpoise.

And Shark? Shark was the operational cipher of the U-boats.

Shark was unique. Every other cipher was produced on a standard three-rotor Enigma machine. But Shark came out of an Enigma with a specially adapted fourth rotor which made it twenty-six times more difficult to break. Only U-boats were allowed to carry it.

It came into service on 1 February 1942 and it blacked out Bletchley almost completely.

Jericho remembered the months that followed as a prolonged nightmare. Before the advent of Shark, the cryptanalysts in Hut 8 had been able to break most U-boat transmissions within a day of interception, allowing ample time to re-route convoys around the wolf packs of German submarines. But in the ten months after the introduction of Shark they read the traffic on just three occasions, and even then it took them seventeen days each time, so that the intelligence, when it did arrive, was virtually useless, was ancient history.

To encourage them in their labours a graph was posted in the code-breakers' hut, showing the monthly tonnages of shipping sunk by the U-boats in the North Atlantic. In January, before the blackout, the Germans destroyed forty-eight Allied ships. In February they sank seventy-three. In March, ninety-five. In May, one hundred and twenty…

'The weight of our failure,' said Skynner, the head of the Naval Section, in one of his portentous weekly addresses, 'is measured in the bodies of drowned men.'

In September, ninety-five ships were sunk. In November, ninety-three…

And then came Fasson and Grazier.

Somewhere in the distance the college clock began to toll. Jericho found himself counting the chimes.

'Are you all right, old thing? You've gone terribly silent.'

'Sorry. I was just thinking. Do you remember Fasson and Grazier?'

'Fasson and who? Sorry, I don't think I ever met them.'

'No. Nor did I. None of us did.'

Fasson and Grazier. He never knew their Christian names. A first lieutenant and an able-bodied seaman. Their destroyer had helped trap a U-boat, the U-459, in the eastern Mediterranean. They had depth-charged her and forced her to the surface. It was about ten o'clock at night. A rough sea, a wind blowing up. After the surviving Germans had abandoned the submarine, the two British sailors had stripped off and swum out to her, lit by searchlights. The U-boat was already low in the waves, holed in the conning tower by cannon fire, shipping water fast. They'd brought off a bundle of secret papers from the radio room, handing them to a boarding party in a boat alongside, and had just gone back for the Enigma machine itself when the U-boat suddenly went bows up and sank. They went down with her – half a mile down, the Navy man had said when he told them the story in Hut 8. 'Let's just hope they were dead before they bit the bottom.'

And then he'd produced the code books. This was on 24 November 1942. More than nine and a half months into the blackout.

At first glance they scarcely looked worth the cost of two men's lives: two little pamphlets, the Short Signal Book and the Short Weather Cipher, printed in soluble ink on pink blotting paper, designed to be dropped into water by the wireless operator at the first sign of trouble. But to Bletchley they were beyond price, worth more than all the sunken treasure ever raised in history. Jericho knew them by heart even now. He closed his eyes and the symbols were still there, burned into the back of his retina.

T = Lufttemperatur in ganzen Celsius-Graden. -28C = a. -27C = b. -26C…

U-boats made daily weather reports: air temperature, barometric pressure, wind-speed, cloud-cover…

The Short Weather Cipher book reduced that data to a half-dozen letters. Those half-dozen letters were enciphered on the Enigma. The message was then broadcast from the submarine in Morse code and picked up by the German Navy's coastal weather stations. The weather stations used the U-boats' data to compile meteorological reports of their own. These reports were then re-broadcast, an hour or two later, in a standard three-rotor Enigma weather cipher – a cipher Bletchley could break – for the use of every German vessel.

It was the back door into Shark.

First, you read the weather report. Then you put the weather report back into the short weather cipher. And what you were left with, by a process of logical deduction, was the text that had been fed into the four-rotor Enigma a few hours earlier. It was a perfect crib. A cryptanalyst's dream.

But still they couldn't break it.

Every day the code-breakers, Jericho among them, fed their possible solutions into the bombes – immense electro-mechanical computers, each the size of a walk-in wardrobe, which made a noise like a knitting machine – and waited to be told which guess was correct. And every day they received no answer. The task was simply too great. Even a message enciphered on a three-rotor enigma might take twenty-four hours to decode, as the bombes clattered their way through the billions of permutations. A four-rotor Enigma, multiplying the numbers by a factor of twenty-six, would theoretically take the best part of a month.

For three weeks Jericho worked round the clock, and when he did grab an hour or two's sleep it was only to dream fitfully of drowning men. 'Let's just hope they were dead before they hit the bottom… 'His brain was beyond tiredness. It ached physically, like an overworked muscle. He began to suffer blackouts. These only lasted a matter of seconds but they were frightening enough. One moment he might be working in the Hut, bent over his slide-rule, and the next everything around him had blurred and jumped on, as if a film had slipped its sprockets in a projector. He managed to beg some Benzedrine off the camp doctor but that only made his mood swings worse, his frenzied highs followed by increasingly protracted lows.

Curiously enough, the solution, when it came, had nothing to do with mathematics, and afterwards he was to reproach himself furiously for becoming too immersed in detail. If he had not been so tired, he might have stepped back and seen it earlier.

It was a Saturday night, the second Saturday in December. At about nine o'clock Logie had sent him home. Jericho had tried to argue, but Logie had said: 'No, you're going to kill yourself if you go on at this rate, and that won't be any use to anyone, old love, especially you.' So Jericho had cycled wearily back to his digs above the pub in Shenley Church End and had crawled beneath the bedclothes. He heard last orders called downstairs, listened as the final few regulars departed and the bar was closed up. In the dead hours after midnight he lay looking at the ceiling wondering if he would ever sleep again, his mind churning like a piece of machinery he couldn't switch off.

It had been obvious from the moment Shark had first surfaced that the only acceptable, long-term solution was to redesign the bombes to take account of the fourth rotor. But that was proving a nightmarishly slow process. If only they could somehow complete the mission Fasson and Grazier had begun so heroically and steal a Shark Enigma. That would make the redesign easier. But Shark Enigmas were the crown jewels of the German Navy. Only the U-boats had them. Only the U-boats and, of course, U-boat communication headquarters in Sainte-Assise, southeast of Paris.

A commando raid on Sainte-Assise, perhaps? A parachute drop? He played with the image for a moment and then dismissed it. Impossible. And, in any case, useless. Even if, by some miracle, they got away with a machine, the Germans would know about it, and switch to a different system of communications. Bletchley's future rested on the Germans continuing to believe that Enigma was impregnable. Nothing could ever be done which might jeopardise that confidence. Wait a minute. Jericho sat upright. Wait a bloody minute.

If only the U-boats and their controllers in Saint-Assise were allowed to have four-rotor Enigmas – and Bletchley knew for a fact that that was the case – how the hell were the coastal weather stations deciphering the U-boat's transmissions?

It was a question no one had bothered to stop and ask, yet it was fundamental.

To read a message enciphered on a four-rotor machine you had to have a four-rotor machine.

Or did you?

If it is true, as someone once said, that genius is 'a zigzag of lightning across the brain', then, in that instant, Jericho knew what genius was. He saw the solution lit up like a landscape before him.

He seized his dressing gown and pulled it over his pyjamas. He grabbed his overcoat, his scarf, his socks and his boots and in less than a minute he was on his bike, wobbling down the moonlit country lane towards the Park. The stars were bright, the ground was iron-hard with frost. He felt absurdly euphoric, laughing like a madman, steering directly into the frozen puddles along the edge of the road, the ice crusts rupturing under his tyres like drum skins. Down the hill he freewheeled into Bletchley. The countryside fell away and the town spread out beneath him in the moonlight, familiarly drab and ugly but on this night beautiful, as beautiful as Prague or Paris, perched on either bank of a gleaming river of railway tracks. In the still air he could hear a train half a mile away being shunted in the sidings – the sudden, frantic chugging of a locomotive followed by a series of clanks, then a long exhalation of steam. A dog barked and set off another. He passed the church and the war memorial, braked to avoid skidding on the ice, and turned left into Wilton Avenue.

He was panting with exertion by the time he reached the Hut, fifteen minutes later, so much so he could barely blurt out his discovery and catch his breath and stop himself from laughing at the same time:'- They're – using – it – as – a – three-rotor – machine – they're – leaving – the – fourth – rotor – in – neutral – when – they – do – the – weather – stuff- the – silly – bloody – buggers -'

His arrival caused a commotion. The night shift all stopped working and gathered in a concerned half-circle round him – he remembered Logie, Kingcome, Puck and Proudfoot – and it was clear from their expressions they thought he really had gone mad. They sat him down and gave him a mug of tea and told him to take it again, slowly, from the beginning.

He went through it once more, step by step, suddenly anxious there might be a flaw in his logic. Four-rotor Enigmas were restricted to U-boats and Sainte-Assise: correct? Correct. Therefore, coastal stations could only decipher three-rotor Enigma messages: correct? Pause. Correct. Therefore, when the U-boats sent their weather reports, the wireless operators must logically disengage the fourth rotor, probably by setting it at zero.

After that, everything happened quickly. Puck ran along the corridor to the Big Room and laid out the best of the weather cribs on one of the trestle tables. By 4 A.M. they had a menu for the bombes. By breakfast one of the bombe bays was reporting a drop and Puck ran through the canteen like a schoolboy shouting: 'It's out! It's out!'

It was the stuff of legend.

At midday Logie telephoned the Admiralty and told the Submarine Tracking Room to stand by. Two hours later, they broke the Shark traffic for the previous Monday and the Teleprincesses, the gorgeous girls in the Teleprinter Room, began sending the translated decrypts down the line to London. They were indeed the crown jewels. Messages to raise the hairs on the back of your neck.

FROM: U-BOAT TO CAPTAIN SCHRODER

FORCED TO SUBMERGE BY DESTROYERS. NO CONTACT. LAST POSITION OF ENEMY AT 0815 NAVAL GRID SQUARE 1849.

COURSE 45 DEGREES, SPEED 9 KNOTS.

FROM: GILADORNE

HAVE ATTACKED. CORRECT POSITION OF CONVOY IS AK1984. 050 DEGREES. AM RELOADING AND KEEPING CONTACT.

FROM: HAUSE

AT 0115 IN SQUARE 3969 ATTACKED, FLARES AND GUNFIRE, DIVED, DEPTH CHARGES. NO DAMAGE. AM IN NAVAL GRID SQUARE AJ3996. ALL TIN FISH, 70 CBM.

FROM: FLAG OFFICER, U-BOATS

TO: 'DRAUFGANGER' WOLF PACK

TOMORROW AT 1700 BE IN NEW PATROL LINE FROM NAVAL GRID SQUARE AK2564 TO 2994. OPERATIONS AGAINST EASTBOUND CONVOY WHICH AT 1200/7/12 WAS IN NAVAL GRID SQUARE AK4189. COURSE 050 TO 070 DEGREES. SPEED APPROX 8 KNOTS.

By midnight they had broken, translated and teleprintered to London ninety-two Shark signals giving the Admiralty the approximate whereabouts and tactics of half the Germans' U-boat fleet.

Jericho was in the Bombe Hut when Logie found him. He had been chasing about for the best part of nine hours and now he was supervising a changeover on one of the machines, still wearing his pyjamas under his overcoat, to the great amusement of the Wrens who tended the bombe. Logie clasped Jericho's hand in both of his and shook it vigorously.

'The Prime Minister!' he shouted in Jericho's ear, above the clattering of the bombes.

'What?'

'The Prime Minister has just been on the telephone with his congratulations!'

Logie's voice seemed a long way away. Jericho bent forward to hear better what Churchill had said and then the concrete floor melted beneath his feet and he was pitching forward into darkness.

'Is,'said Jericho.

'What, old thing?'

'Just now, you said Shark was a monster and then you said it w a monster.' He pointed the fork at Logie. 'I know why you've come. You've lost it, haven't you?'

Logie grunted and stared into the fire and Jericho felt as though someone had laid a stone on his heart. He sat back in his chair, shaking his head, then gave a snort of laughter.

'Thank you, Tom,' said Logie, quietly. 'I'm glad you find it funny.'

'And all the time I thought you'd come here to give me the push. That's funny. That's pretty funny, isn't it, old thing?'

'What day is it today?' asked Logie. 'Friday.'

'Right, right.' Logie extinguished his pipe with his thumb and stuffed it into his pocket. He sighed. 'Let me see. That means it must have happened on Monday. No, Tuesday. Sorry. We haven't had a lot of sleep lately.'

He passed a hand through his thinning hair and Jericho noticed for the first time that he'd turned quite grey. So it's not just me, he thought, it's all of us, we're all falling to pieces. No fresh air. No sleep. Not enough fresh food. Six-day weeks and twelve-hour days…

'We were still just about ahead of the game when you left,' said Logie. 'You know the drill. Of course you do. You wrote the bloody book. We'd wait for Hut 10 to break the main naval weather cipher, then, by lunch time, with a bit of luck we'd have enough cribs to tackle the day's short weather codes. That would give us three of the four rotor settings and then we'd get stuck into Shark. The time-lag varied. Sometimes we'd break it in one day, sometimes three or four. Anyway, the stuff was gold-dust and we were Whitehall's blue-eyed boys.'

'Until Tuesday.'

'Until Tuesday.' Logie glanced at the door and dropped his voice. 'It's an absolute tragedy, Tom. We'd cut losses in the North Atlantic by 75 per cent. That's about three hundred thousand tons of shipping a month. The intelligence was amazing. We knew where the U-boats were almost as precisely as the Germans did. Of course, looking back, it was too good to last. The Nazis aren't fools. I always said: "Success in this game breeds failure, and the bigger the success, the bigger the failure's likely to be." You'll remember me saying it. The other side gets suspicious, you see. I said -'

'What happened on Tuesday, Guy?'

'Right-ho. Sorry. Tuesday. It was about eight in the evening. We got a call from one of the intercept stations. Flowerdown, I think, but Scarborough heard it too. I was in the canteen. Puck came and fetched me out. They'd started picking up something in the early afternoon. A single word, broadcast on the hour, every hour. It was coming out of Sainte-Assise on both main U-boat radio nets.'

'This word was enciphered in Shark, I take it?'

'No, that's just it. That's what they were so excited about. It wasn't in cipher. It wasn't even in Morse. It was a human voice. A man. Repeating this one word: Akelei'

'Akelei,' murmured Jericho. 'Akelei… That's a flower, isn't it?'

'Ha!' Logie clapped his hands. 'You are a bloody marvel, Tom. See how much we miss you? We had to go and ask one of the German swots on Z-watch what it meant. Akelei: a five-petalled flower of the buttercup family, from the Latin Aquilegia. We vulgarians call it columbine.'

'Akelei? repeated Jericho. 'This is a prearranged signal of some sort, presumably?'

'It is.'

'And it means?'

'It means trouble, is what it means, old love. We found out just how much trouble at midnight yesterday.' Logie leaned forwards. The humour had left his voice. His face was lined and grave. 'Akelei means: "Change the Short Weather Code Book." They've gone over to a new one and we haven't a bloody clue what to do about it. They've closed off our way into Shark, Tom. They've blacked us out again.'

It didn't take Jericho long to pack. He'd bought nothing since he arrived in Cambridge except a daily newspaper, so he took out exactly what he'd carried in three weeks earlier: a pair of suitcases filled with clothes, a few books, a fountain pen, a slide rule and pencils, a portable chess set and a pair of walking boots. He laid his cases on the bed and moved slowly about the room collecting his possessions while Logie watched him from the doorway.

Running round and round in his head, unbidden from some hidden depth in his subconscious, was a nursery rhyme: 'For want of a nail, the horse was lost; for want of a horse, the rider was lost; for want of a rider, the battle was lost; for want of a battle, the kingdom was lost; and all for the want of a horseshoe nail…'

He folded a shirt and laid it on top of his books.

For want of a Short Weather Code Book they might lose the Battle of the Atlantic. So many men, so much material, threatened by so small a thing as a change in weather codes. It was absurd.

'You can always tell a boarding-school boy,' said Logie, 'they travel light. All those endless train journeys, I suppose.'

'I prefer it.'

He stuffed a pair of socks down the side of the case. He was going back. They wanted him back. He couldn't decide whether he was elated or terrified.

'You don't have much stuff in Bletchley, either, do you?'

Jericho swung round to look at him. 'How do you know that?'

'Ah.' Logie winced with embarrassment. 'I'm afraid we had to pack up your room, and, ah, give it to someone else. Pressure of space and all that.'

'You didn't think I'd be coming back?'

'Well, let's say we didn't know we'd need you back so soon. Anyway, there's fresh digs for you in town, so at least it'll be more convenient. No more long cycle rides late at night.'

'I rather like long cycle rides late at night. They clear the mind.' Jericho closed the lids on the suitcases and snapped the locks.

I say, you are up to this, old love? Nobody wants to force you into anything.'

'I'm a damn sight fitter than you are, by the look of you.'

'Only I'd hate you to feel pressured…'

'Oh do shut up, Guy.'

'Right-ho. I suppose we haven't left you with much choice, have we? Can I help you with those?'

'If I'm well enough to go back to Bletchley, I'm well enough to manage a couple of suitcases.'

He carried them to the door and turned off the light. In the sitting room he extinguished the gas fire and took a last look around. The overstuffed sofa. The scratched chairs. The bare mantelpiece. This was his life, he thought, a succession of cheaply furnished rooms provided by English institutions: school, college, government. He wondered what the next room would be like. Logie opened the doors and Jericho turned off the desk light.

The staircase was in darkness. The bulb had long since died. Logie got them down the stone steps by striking a series of matches. At the bottom, they could just make out the shape of Leveret, standing guard, his silhouette framed against the black mass of the chapel. He turned round. His hand went to his pocket.

'All right, Mr Leveret,' said Logie. 'It's only me. Mr Jericho's coming with us.'

Leveret had a blackout torch, a cheap thing swathed in tissue paper. By its pale beam, and by the faint residue of light still left in the sky, they made their way through the college. As they walked alongside the Hall they could hear the clatter of cutlery and the sound of the diners' voices, and Jericho felt a pang of regret. They passed the Porter's Lodge and stepped through the man-sized gate cut in the big oak door. A crack of light appeared in one of the lodge's windows as someone inside pulled back the curtain a fraction. With Leveret in front of him and Logie behind, Jericho had a curious sensation of being under arrest.

The deputy director's Rover was pulled up on the cobbled pavement. Leveret carefully unlocked it and ushered them into the back seat. The interior was cold and smelled of old leather and cigarette ash. As Leveret was stowing the suitcases in the boot Logie said suddenly: 'Who's Claire, by the way?'

'Claire?' Jericho heard his voice in the darkness, guilty and defensive.

'When you came up the staircase I thought I heard you shouting "Claire". Claire?' Logie gave a low whistle. 'I say, she's not the arctic blonde in Hut 3, is she? I bet she is. You lucky bugger.,.'

Leveret started the engine. It stuttered and backfired. He let out the brake and the big car rocked over the cobbles on to King's Parade. The long street was deserted in both directions. A wisp of mist shone in the shaded headlamps. Logie was still chuckling to himself as they swung left.

'I bet she jolly well is. You lucky, lucky bugger…'

Kite stayed at his post by the window, watching the red tail-lights until they vanished past the corner of Gonville and Caius. He, let the curtain drop.

Well, well…

This would give them something to talk about the next morning. Listen to this, Dottie. Mr Jericho was taken away at dead of night – oh, all right then, eight o'clock – by two men, one a tall fellow and the other very obviously a plain clothes copper. Escorted from the premises and not a word to anyone. The tall chap and the copper had arrived about five o'clock while the young master was still out walking and the big one -the detective, presumably – had asked Kite all sorts of questions: 'Has he seen anyone since he's been here? Has he written to anyone? Has anyone written to him? What's he been doing?' Then they'd taken his keys and searched Jericho's room before Jericho got back.

It was murky. Very murky.

A spy, a genius, a broken heart – and now what? A criminal of some sort? Quite possibly. A malingerer? A runaway? A deserter! Yes, that was it: a deserter!

Kite went back to his seat by the stove and opened his evening paper.

NAZI SUB TORPEDOES PASSENGER LINER, he read. WOMEN AND CHILDREN LOST.

Kite shook his head at the wickedness of the world. It was disgusting, a young man of that age, not wearing uniform, hiding away in the middle of England while mothers and kiddies were being killed.