Enigma

  ‘Of course, the weather’s appalling,’ added Cave, his sharp voice cutting in to the silence, ‘even for the time of year. Snow. Freezing fog. Green water breaking over the bows. That’s actually in our favour.’

  Kramer said: ‘How long do we have?’

  ‘Less time than we originally thought, that’s for certain. The U-boat is faster than any convoy, but it’s still a slow beast. On the surface it moves at the speed of a man on a bicycle, underwater it’s only as fast as a man on foot. But if Dönitz knows about the convoys? Perhaps a day and a half. The bad weather will give them visibility problems. Even so – yes – I’d guess a day and a half at the outside.’

  Cave excused himself to go and telephone the bad news to the Admiralty. The cryptanalysts were left alone. At the far end of the hut a faint clacking noise began as the Type-X machines started their day’s work.

  ‘That’ll be D-D-Dolphin,’ said Pinker. ‘Will you excuse me, G-G-Guy?’

  Logie raised a hand in benediction and Pinker hurried out of the room.

  ‘If only we had a four-wheel bombe,’ moaned Proudfoot.

  ‘Well, we ain’t got one, old love, so don’t let’s waste time on that.’

  Kramer had been leaning against one of the trestle tables. Now he pushed himself on to his feet. There wasn’t room for him to pace, so he performed a kind of restless shuffle, smacking his fist into the palm of his left hand.

  ‘Goddamn it, I feel so helpless. A day and a half. A measly, goddamn day and a half. Jesus! There must be something. I mean, you guys did break this thing once, didn’t you, during the last blackout?’

  Several people spoke at once.

  ‘Oh, yes.’

  ‘D’you remember that?’

  ‘That was Tom.’

  Jericho wasn’t listening. Something was stirring in his mind, some tiny shift in the depths of his subconscious, beyond the reach of any power of analysis. What was it? A memory? A connection? The more he tried to concentrate on it, the more elusive it became.

  ‘Tom?’

  He jerked his head up in surprise.

  ‘Lieutenant Kramer was asking you, Tom’ said Logie, with weary patience, ‘about how we broke Shark during the blackout.’

  ‘What?’ He was irritated at having his thoughts interrupted. His hands fluttered. ‘Oh, Dönitz was promoted to admiral. We took a guess that U-boat headquarters would be pleased as Punch. So pleased, they’d transmit Hitler’s proclamation verbatim to all boats.’

  ‘And did they?’

  ‘Yes. It was a good crib. We put six bombes onto it. Even then it still took us nearly three weeks to read one day’s traffic.’

  ‘With a good crib?’ said Kramer. ‘Six bombes. Three weeks?’

  ‘That’s the effect of a four-wheel Enigma.’

  Kingcome said: ‘It’s a pity Dönitz doesn’t get a promotion every day.’

  This immediately brought Atwood to life. ‘The way things are going, he probably will.’

  Laughter momentarily lightened the gloom. Atwood looked pleased with himself.

  ‘Very good, Frank,’ said Kingcome. ‘A daily promotion. Very good.’

  Only Kramer refused to laugh. He folded his arms and stared down at his gleaming shoes.

  They began to talk about some theory of de Brooke’s which had been running on a pair of bombes for the past nine hours, but the methodology was hopelessly skewed, as Puck pointed out.

  ‘Well, at least I’ve had an idea,’ said de Brooke, ‘which is more than you have.’

  ‘That is because, my dear Arthur, if I have a terrible idea, I keep it to myself.’

  Logie clapped his hands. ‘Boys, boys. Let’s keep the criticism constructive, shall we?’

  The conversation dragged on but Jericho had stopped listening a long time ago. He was chasing the phantom in his mind again, searching back through his mental record of the past ten minutes to find the word, the phrase, that could have stirred it into life. Diana, Hubertus, Magdeburg, picket line, radio silence, contact signal …

  Contact signal.

  ‘Guy, where d’you keep the keys to the Black Museum?’

  ‘What, old thing? Oh, in my desk. Top right-hand drawer. Hey, where’re you going? Just a minute, I haven’t finished talking to you yet …’

  It was a relief to get out of the claustrophobic atmosphere of the hut and into the cold, fresh air. He trotted up the slope towards the mansion.

  He seldom went into the big house these days but whenever he did it reminded him of a stately home in a twenties murder mystery. (‘You will recall, inspector, that the colonel was in the library when the fatal shots were fired …’) The exterior was a nightmare, as if a giant handcart full of the discarded bits of other buildings had been tipped out in a heap. Swiss gables, Gothic battlements, Greek pillars, suburban bay windows, municipal red brick, stone lions, the entrance porch of a cathedral – the styles sulked and raged against one another, capped by a bell-shaped roof of beaten green copper. The interior was pure Gothic horror, all stone arches and stained glass windows. The polished floors rang hollow beneath Jericho’s feet and the walls were decorated with dark wooden panelling of the sort that springs open in the final chapter to reveal a secret labyrinth. He was hazy about what went on here now. Commander Travis had the big office at the front looking out over the lake while upstairs in the bedrooms all sorts of mysterious things were done: he’d heard rumours they were breaking the ciphers of the German Secret Service.

  He walked quickly across the hall. An Army captain loitering outside Travis’s office was pretending to read that morning’s Observer, listening to a middle-aged man in tweeds trying to chat up a young RAF woman. Nobody paid any attention to Jericho. At the foot of the elaborately carved oak staircase, a corridor led off to the right and wound around the back of the house. Midway along it was a door which opened to reveal steps down to a secondary passage. It was here, in a locked room in the cellar, that the cryptanalysts from huts 6 and 8 stored their stolen treasures.

  Jericho felt along the wall for the light switch.

  The larger of the two keys unlocked the door to the museum. Stacked on metal shelves along one wall were a dozen or more captured Enigma machines. The smaller key fitted one of a pair of big iron safes. Jericho knelt and opened it and began to rummage through the contents. Here they all were, their precious pinches: each one a victory in the long war against the Enigma. There was a cigar box with a label dated February 1941, containing the haul from the armed German trawler Krebs: two spare rotors, the Kriegsmarine grid map of the North Atlantic and the naval Enigma settings for February 1941. Behind these was a bulging envelope marked München – a weather ship whose capture three months after the Krebs had enabled them to break the meterological code – and another labelled ‘U-110’. He pulled out armfuls of papers and charts.

  Finally, from the bottom shelf at the back, he withdrew a small package wrapped in brown oilcloth. This was the haul for which Fasson and Grazier had died, still in its original covering, as it had been passed out of the sinking U-boat. He never saw it without thanking God that they’d found something waterproof to wrap it in. The smallest exposure to water would have dissolved the ink. To have plucked it from a drowning submarine, at night, in a high sea … It was enough to make even a mathematician believe in miracles. Jericho removed the oilcloth tenderly, as a scholar might unwrap the papyri of an ancient civilisation, or a priest uncover holy relics. Two little pamphlets, printed in Gothic lettering on pink blotting paper. The second edition of the U-boats’ Short Weather Cipher, now useless, thanks to the code book change. And – exactly as he had remembered – the Short Signal Book. He flicked through it. Columns of letters and numbers.

  A typed notice was stuck on the back of the safe door: ‘It is strictly forbidden to remove any item without my express permission. (Signed) L.F.N. Skynner, Head of Naval Section.’

  Jericho took particular pleasure in slipping the Short Signal Book into his inside pocket and running wit
h it back to the hut.

  Jericho tossed the keys to Logie who fumbled and then just caught them.

  ‘Contact signal.’

  ‘What?’

  ‘Contact signal,’ repeated Jericho.

  ‘Praise the Lord!’ said Atwood, throwing up his hands like a revivalist preacher. ‘The Oracle has spoken.’

  ‘All right, Frank. Just a minute. What about it, old love?’

  Jericho could see it all much faster than he could convey it. Indeed, it was quite hard to formulate it in words at all. He spoke slowly, as if translating from a foreign language, reordering it in his mind, turning it into a narrative.

  ‘Do you remember, in November, when we got the Short Weather Cipher Book off the U-459? When we also got the Short Signal Book? Only we decided not to concentrate on the Short Signal Book at the time, because it never yielded anything long enough to make a worthwhile crib? I mean, a convoy contact signal on its own, it isn’t worth a damn, is it? It’s just five letters once in a blue moon.’ Jericho withdrew the little pink pamphlet carefully from his pocket. ‘One letter for the speed of the convoy, a couple for its course, a couple more for the grid reference …’

  Baxter stared at the code book as if hypnotised. ‘You’ve removed that from the safe without permission?’

  ‘But if Lieutenant Cave is correct, and whichever U-boat finds the convoy is going to send a contact signal every two hours, and if it’s going to shadow it till nightfall, then it’s possible – theoretically possible – it might send as many as four, or even five signals, depending on what time of day it makes its first sighting.’ Jericho sought out the only uniform in the room. ‘How long does daylight last in the North Atlantic in March?’

  ‘About twelve hours,’ said Kramer.

  ‘Twelve hours, you see? And if a number of other U-boats attach themselves to the same convoy, on the same day, in response to the original signal, and they all start sending contact signals every two hours …’

  Logie, at least, could see what he was driving at. He withdrew his pipe slowly from his mouth. ‘Bloody hell!’

  ‘Then again, theoretically, we could have, say, twenty letters of crib off the first boat, fifteen off the second – I don’t know, if it’s an attack by eight boats, let’s say, we could easily get to a hundred letters. It’s just as good as the weather crib.’ Jericho felt as proud as a father, offering the world a glimpse of his newborn child. ‘It’s beautiful, don’t you see?’ He gazed at each of the cryptanalysts in turn: Kingcome and Logie were beginning to look excited, de Brooke and Proudfoot seemed thoughtful, Baxter, Atwood and Puck appeared downright hostile. ‘It was never possible till this moment, because until now the Germans have never been able to throw so many U-boats against such a mass of shipping. It’s the whole story of Enigma in a nutshell. The very scale of the Germans’ achievement breeds such a mass of material for us, it’ll sow the seeds of their eventual defeat.’

  He paused.

  ‘Aren’t there rather a lot of ifs there?’ said Baxter drily. ‘If the U-boat finds the convoy early enough in the day, if it reports every two hours, if the others all do the same, if we manage to intercept every transmission …’

  ‘And if,’ said Atwood, ‘the Short Signal Book we pinched in November wasn’t changed last week at the same time as the Weather Cipher Book …’

  That was a possibility Jericho hadn’t considered. He felt his enthusiasm crumble slightly.

  Now Puck joined in the attack. ‘I agree. The concept is quite brilliant, Thomas. I applaud your – inspiration, I suppose. But your strategy depends on failure, does it not? We will only break Shark, on your admission, if the U-boats find the convoy, which is exactly what we want to avoid. And suppose we do come up with that day’s Shark settings – so what? Marvellous. We can read all the U-boats’ signals to Berlin, boasting to Dönitz about how many Allied ships they’ve sunk. And twenty-four hours later, we’re blacked out again.’

  Several of the cryptanalysts groaned in agreement.

  ‘No, no,’ Jericho shook his head emphatically. ‘Your logic is flawed, Puck. What we hope, obviously, is that the U-boats don’t find the convoys. Yes – that’s the whole point of the exercise. But if they do, we can at least turn it to our advantage. And it won’t just be one day, not if we’re lucky. If we break the Shark settings for twenty-four hours, then we’ll pick up the encoded weather messages for that entire period. And, remember, we’ll have our own ships in the area, able to give us the precise weather data the U-boats are encoding. We’ll have the plaintext, we’ll have the Shark cipher settings, so we’ll be able to make a start on reconstructing the new Weather Code Book. We could get our foot back in the door again. Don’t you see?’

  He ran his hands through his hair and tugged at it in exasperation. Why were they all being so dim?

  Kramer had been scribbling furiously in a notebook. ‘He’s on to something, you know.’ He tossed his pencil into the air and caught it. ‘Come on. It’s worth a try. At least it puts us back in the fight.’

  Baxter grunted. ‘I still don’t see it.’

  ‘Nor do I,’ said Puck.

  ‘I suppose you don’t see it, Baxter,’ said Atwood, ‘because it doesn’t represent a triumph for the world proletariat?’

  Baxter’s hands curled into fists. ‘One of these days, Atwood, someone’s going to knock your bloody smug block off.’

  ‘Ah. The first impulse of the totalitarian mind: violence.’

  ‘Enough!’ Logie banged his pipe like a gavel on one of the trestle tables. None of them had ever heard him shout before and the room went quiet. ‘We’ve had quite enough of that already.’ He stared hard at Jericho. ‘Now, it’s quite right we should be cautious. Puck, your point’s taken. But we’ve also got to face facts. We’ve been blacked out four days and Tom’s is the only decent idea we’ve got. So bloody good work, Tom.’

  Jericho stared at an ink stain on the floor. Oh God, he thought, here comes the housemaster’s pep talk.

  ‘Now, there’s a lot resting on us here, and I want every man to remember he’s part of a team.’

  ‘No man is an island, Guy,’ said Atwood, deadpan, his chubby hands clasped piously on his wide stomach.

  ‘Thank you, Frank. Quite right. No they’re not. And if ever any of us – any of us – is tempted to forget it, just think of those convoys, and all the other convoys this war depends on. Got it? Good. Right. Enough said. Back to work.’

  Baxter opened his mouth to protest, but then seemed to think better of it. He and Puck exchanged grim glances on their way out. Jericho watched them go and wondered why they were so determinedly pessimistic. Puck couldn’t abide Baxter’s politics and normally the two men kept their distance. But now they seemed to have made common cause. What was it? A kind of academic jealousy? Resentment that he had come in after all their hard work and made them look like fools?

  Logie was shaking his head. ‘I don’t know, old love, what are we to do with you?’ He tried to look stern, but he couldn’t hide his pleasure. He put his hand on Jericho’s shoulder.

  ‘Give me my job back.’

  ‘I’ll have to talk to Skynner.’ He held the door open and ushered Jericho out into the passage. The three Wrens watched them. ‘My God,’ said Logie, with a shudder. ‘Can you imagine what he’s going to say? He’s going to love it, isn’t he, having to tell his friends the admirals that the best chance of getting back into Shark is if the convoys are attacked? Oh, bugger, I suppose I’d better go and call him.’ He went halfway into his office, then came out again. ‘And you’re quite sure you never actually hit him?’

  ‘Quite sure, Guy.’

  ‘Not a scratch?’

  ‘Not a scratch.’

  ‘Pity, said Logie, half to himself. ‘In a way. Pity.’

  5

  Hester Wallace couldn’t sleep. The blackout curtains were drawn against the day. Her tiny room was a study in monochrome. A nosegay of lavender sent a soothing fragrance filtering through her pi
llow. But even though she lay dutifully on her back in her cotton nightgown, her legs pressed together, her hands folded on her breast, like a maiden on a marble tomb, oblivion still eluded her.

  ‘ADU, Miss Wallace. Angels Dance Upwards …’

  The mnemonic was infuriatingly effective. She couldn’t get it out of her brain, even though the arrangement of letters meant nothing to her.

  ‘It’s a call sign. Probably German Army or Luftwaffe …’

  No surprise in that. It was almost bound to be. After all, there were so many of them: thousands upon thousands. The only reliable rule was that Army and Luftwaffe call-signs never began with a D, because D always indicated a German commercial station.

  ADU … ADU …

  She couldn’t place it.

  She turned on her side, brought her knees up to her stomach and tried to fill her mind with soothing thoughts. But no sooner had she rid herself of the intense, pale face of Tom Jericho than her memory showed her the wizened priest of St Mary’s, Bletchley, that croaking mouthpiece of St Paul’s misogynies. ‘It is a shame for women to speak in the church …’ (1 Corinthians 14.xxxv). ‘Silly women laden with sins, led away with divers lusts …’ (2 Timothy 3.vi). From such texts he had woven a polemical sermon against the wartime employment of the female sex – women driving lorries, women in trousers, women drinking and smoking in public houses unaccompanied by their husbands, women neglecting their children and their homes. ‘As a jewel of gold in a swine’s mouth, so is a fair woman which is without discretion.’ (Proverbs 1 1.xxii).

  If only it were true! she thought. If only women had usurped authority over men! The Brylcreemed figure of Miles Mermagen, her head of section, rose greasily before her inner eye. ‘My dear Hester, a transfer at the present moment is really quite out of the question.’ He had been a manager at Barclays Bank before the war and liked to come up behind the girls as they worked and massage their shoulders. At the Hut 6 Christmas Party he had manoeuvred her under the mistletoe and clumsily taken off her glasses. (‘Thank you, Miles,’ she’d said, trying miserably to make a joke of it, ‘without my spectacles you too look almost tolerably attractive …’) His lips on hers were unpleasantly moist, like the underside of a mollusc, and tasted of sweet sherry.