Between Silk and Cyanide: A Codemaker's War, 1941-1945

Between Silk and Cyanide: A Codemaker's War, 1941-1945

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by Leo Marks

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In 1942, with a black-market chicken tucked under his arm by his mother, Leo Marks left his father's famous bookshop, 84 Charing Cross Road, and went off to fight the war. He was twenty-two. Soon recognized as a cryptographer of genius, he became head of communications at the Special Operations Executive (SOE), where he revolutionized the codemaking techniques of the…  See more details below


In 1942, with a black-market chicken tucked under his arm by his mother, Leo Marks left his father's famous bookshop, 84 Charing Cross Road, and went off to fight the war. He was twenty-two. Soon recognized as a cryptographer of genius, he became head of communications at the Special Operations Executive (SOE), where he revolutionized the codemaking techniques of the Allies and trained some of the most famous agents dropped into occupied Europe. As a top codemaker, Marks had a unique perspective on one of the most fascinating and, until now, little-known aspects of the Second World War. This stunning memoir, often funny, always gripping and acutely sensitive to the human cost of each operation, provides a unique inside picture of the extraordinary SOE organization at work and reveals for the first time many unknown truths about the conduct of the war.
SOE was created in July 1940 with a mandate from Winston Churchill to "set Europe ablaze." Its main function was to infiltrate agents into enemy-occupied territory to perform acts of sabotage and form secret armies in preparation for D-Day. Marks's ingenious codemaking innovation was to devise and implement a system of random numeric codes printed on silk. Camouflaged as handkerchiefs, underwear, or coat linings, these codes could be destroyed message by message, and therefore could not possibly be remembered by the agents, even under torture.
Between Silk and Cyanide chronicles Marks's obsessive quest to improve the security of agents' codes and how this crusade led to his involvement in some of the war's most dramatic and secret operations. Among the astonishing revelations is his account of the code war between SOE and the Germans in Holland. He also reveals for the first time how SOE fooled the Germans into thinking that a secret army was operating in the Fatherland itself, and how and why he broke the code that General de Gaulle insisted be available only to the Free French. By the end of this incredible tale, truly one of the last great World War II memoirs, it is clear why General Eisenhower credited the SOE, particularly its communications department, with shortening the war by three months. From the difficulties of safeguarding the messages that led to the destruction of the atomic weapons plant at Rjukan in Norway to the surveillance of Hitler's long-range missile base at Peenemünde to the true extent of Nazi infiltration of Allied agents, Between Silk and Cyanide sheds light on one of the least-known but most dramatic aspects of the war.
Writing with the narrative flair and vivid characterization of his famous screenplays, Marks gives free rein to his keen sense of the absurd and wry wit without ever losing touch with the very human side of the story. His close relationship with "the White Rabbit" and Violette Szabo -- two of the greatest British agents of the war -- and his accounts of the many others he dealt with result in a thrilling and poignant memoir that celebrates individual courage and endeavor, without losing sight of the human cost and horror of war.

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Editorial Reviews

New York Times Book Review
[A] spellbinding real-life thriller....A compelling insider's view to the shadow war: intrigue and treachery, double-dealing and deception, hope and despair, triumph and tragedy.
Richard Bernstein
An enthralling book, one full of an eccentric charm as well as fascinating, previously undisclosed details of the secret war waged in the occupied countries.— The New York Times
Ken Ringle
A welcome and powerfully affecting chapter of World War II history, and a very human story of the most clandestine and cerebral art of making war.— The Washington Post
From the Publisher
The New York Times Book Review [A] spellbinding real-life thriller....A compelling insider's view to the shadow war: intrigue and treachery, double-dealing and deception, hope and despair, triumph and tragedy.

Richard Bernstein The New York Times An enthralling book, one full of an eccentric charm as well as fascinating, previously undisclosed details of the secret war waged in the occupied countries.

Ken Ringle The Washington Post A welcome and powerfully affecting chapter of World War II history, and a very human story of the most clandestine and cerebral art of making war.

Martin Scorsese A mesmerizing account of World War II as fought on the home front in Great Britain by the ingenious codemakers whose work determined the life and death of the Allied agents in occupied Europe. Leo Marks, a brilliant cryptographer, is a masterful and passionate storyteller. I was immediately swept into his secret world of codes and "undecipherables," trying at times (without success) to unravel the puzzles myself, and found it difficult to put down the book until the drama had come to an end.

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Chapter One

A Hard Man to Place

In January 1942 I was escorted to the war by my parents in case I couldn't find it or met with an accident on the way. In one hand I clutched my railway warrant -- the first prize I had ever won; in the other I held a carefully wrapped black-market chicken. My mother, who had begun to take God seriously the day I was called up, strode protectively beside me -- praying that the train would never arrive, cursing the Führer when she saw that it had and blessing the porter who found me a seat. Mother would have taken my place if she could, and might have shortened the war if she had.

My father, who was scarcely larger than the suitcases he insisted on carrying, was an antiquarian bookseller whose reading was confined to the spines of books and the contents of the Freemason's Chronicle. His shop was called Marks & Co. and its address was 84 Charing Cross Road. He never read the gentle little myth by Helene Hanff; long before it was published he'd become one himself.

My parents accompanied their only joint venture to the door of the train and, for the first time in twenty years, prepared to relinquish him. Mother's farewell to her only child was the public's first glimpse of open-heart surgery. Late-comers were offered a second. As I entered the carriage clutching my chicken and bowler hat, she called out at the top of her voice -- if it had one -- 'LOOK AFTER MY BOY.'

The captain in the seat opposite me accepted the brief. To distract me from the spectacle of Mother comforting Father and the station master comforting them both, he silently proffered his cigarette case. I indicated my virgin pipe.

'Going far, old son?'

My security-minded nod convinced him, if Mother's performance hadn't already, that I was being dispatched to some distant outpost of what remained of Empire. I was, in fact, going all the way to Bedford.

I had been accepted as a pupil at a school for cryptographers. Gaining admission hadn't been easy: I'd written to the War Office, the Foreign Office and the Admiralty, enclosing specimens of my home-made codes with a curriculum vitae based loosely on fact, but no more loosely than their formal replies stating that my letters were receiving attention. Since codes meant as much to me as Spitfires did to those who had guts, I resolved to make one last try and suddenly remembered that I had a godfather named Major Jack Dermot O'Reilly who worked in the Special Branch at Scotland Yard. I also remembered that Major Jack (like Father) was a Freemason, a branch of the Spiritual Secret Service for which I was still too young.

Arriving at the Special Branch unannounced, I called upon Major Jack carrying my codes in my gas-mask case, which he clearly considered was the most appropriate place for them. However, he must have put his 'Brother' before his country because a few prayers later I was invited by the War Office to attend an interview at Bedford 'to discuss my suitability for certain work of national importance'.

My audition took place at a large private house which tried to ramble but hadn't the vitality. A friendly sergeant told me the CO was expecting me -- and I had my first meeting with Major Masters, the headmaster of the code-breaking school. He began the interview by asking what my hobbies were.

'Incunabula and intercourse, sir.'

It slipped out and wasn't even accurate; I'd had little experience of one and couldn't afford the other. I suspected that he wasn't sure what incunabula was and added: 'And chess too, sir -- when there's time,' which proved a better gambit.

I answered the rest of his questions honestly -- with one exception. He asked me how I first became interested in codes. There is only one person to whom I've ever told the truth about this and we hadn't yet met. The reply I concocted didn't impress him. I didn't think much else had either.

Three weeks later I received his letter of acceptance.

The school for code-breakers was the only one of its kind in England and its founding father, patron saint and principal customer was Britain's cryptographic supremo, John Tiltman. According to O'Reilly, Tiltman's talent had already received the ultimate Intelligence, accolade: it had made him a bargaining counter with the Americans.

The course was due to last for eight weeks, at the end of which the students would be graded and sent to Bletchley Park, which was Tiltman's workshop and the headquarters of the cryptographic department, known in the trade as MI8.

Fifteen new pupils, including, two young women, had been selected for the course and we sat at separate desks in a large, bright room, studying the mating habits of the alphabet, counting the frequency of letters and working our way. through exercises which gradually became more difficult until we were ready to tackle codes of military and diplomatic level.

For a short while the whole class seemed to be moving in orderly mental convoy towards the promised land of Bletchley. But amongst those potential problem-masters there was one confirmed problem-pupil. I knew that if I didn't break behaviour patterns as well as codes, I would be lucky to last the term -- a prospect which made me keep peace with my teachers for a personal best, of about a week. The regression started when I felt a code of my own simmering inside me. This unwanted pregnancy was accompanied by morning sickness which took the form of questioning the quality of the exercises which were supposed to extend us. I was convinced that the school's methods of teaching would be better suited to a crash course in accountancy. The decline was irreversible when I tried to find quicker ways of breaking codes than the ones prescribed for us, and began to chase cryptographic mirages of my own making. Having somehow absorbed a few tricks of the trade, I spent hours trying to devise codes which would be proof against them. Although possibly not quite the waste of time it was then pronounced to be, this was still chronic indiscipline masquerading as creative impulse.

The chief instructor was a patient, conscientious lieutenant named Cheadle. He wandered round the classroom once a day, peering hopefully over the students' shoulders -- urging us to 'dig out the root problems like a corn'. When he came to my desk, he found nothing to excise. He was like a chiropodist treating a wooden leg which insisted on kicking him.

By the time I was halfway through the course, all the others had reached the final exercise. Since I had no hope of closing the gap, I decided I had nothing to lose by vaulting it. It was strictly against the rules for any student to remove work from the premises; there was no law against memorizing it. By scanning the code until it became my favourite face, I was able to take all its key features home with me, slightly blemished by the spots before my eyes.

'Home' in Bedfordshire, a county which deserved its duke, was a boarding house -- one of many in which the students were billeted. I had been instructed to tell the landlady that I was from the Ministry of Information. At supper time that night mine hostess, as usual, placed a piece of spam beside me and the code surrendered at the sight of it. It laid down its arms and said 'enough'. The rest was just hard work, a matter of gathering it in. Twenty-four hours later I was the proud possessor of a finished exercise.

Nobody had told me that it was intended to be a 'team effort' spread across a week. A bemused Lieutenant Cheadle showed my work to a highly suspicious Major Masters, who immediately tightened internal security. However, as so often happens in such matters, what is tightened at one end becomes loosened at the other and I was able to catch a glimpse of my confidential report.

It might have been written by the high master of St Paul's who would have expelled me had he not been a client of 84's: 'In his determination to find short cuts, he is apt to be slap-dash and erratic...though his approach shows some signs of originality, he is a very hard man to teach and will, I believe, be an even harder one to place...'

I wondered what arrangements Bedford made to dispose of its waste product.

The friendly sergeant was never friendlier than at mid-evening when he was prepared to reveal whatever he had heard on the grapevine in exchange for a little of the grape.

The rest of my course was going to Bletchley. As for its solitary failure, an interview had been arranged for me with 'some potty outfit in Baker Street, an open house for misfits'. If even they didn't want me, I would be regarded as unmarketable.

'It's called Inter Services Research Bureau,' said the sergeant. He lowered his voice. 'It's got another name, too. SOE or SOD or something.'

It had many names, Sergeant.

One of them was Bedlam.

The personnel officer who screened me at 64 Baker Street conducted the entire interview in the mistaken belief that I was closely related to Sir Simon Marks, the head of Marks & Spencer -- an illusion which I was careful to encourage. It took me a little while to grasp what the 'potty outfit' was after from the great outfitters.

The answer was space.

The largest of the many buildings which SOE occupied in and around Baker Street was Michael House -- which had been the headquarters of Marks & Spencer. SOE badly needed extra canteen facilities in Michael House and only Marks & Spencer could grant them. The personnel officer made it clear that Sir Simon had already proved to be a most accommodating landlord and SOE was reluctant to impose upon him further.

If I was decoding the gist correctly, he was trying to assess whether I was suitably disposed to use my good offices to Canvass even better ones. Unfortunately I had never met Sir Simon -- but even more unfortunately, I had met, and couldn't stop meeting, his only son Michael, the heir-presumptive to the kingdom of M & S. We had had the incinerating experience of going to several schools together, including St Paul's, of being put in the same classes, and of being mistaken for brothers. We had finally tossed a coin (his) to decide which of us would change his name, an arrangement which he failed to honour. The princeling had not been a bit impressed when his father named Michael House after him, but he'd woken up sharply when Sir Simon offered him a cash bonus for every unwrapped orange he found in a Marks & Spencer store. I imparted these 'hot' family titbits to the enthralled personnel officer, and before he could enquire where Leo House was I assured him that I would nudge Sir Simon in the right direction the next time we dined together. A few days after this solemn undertaking 'Uncle Simon' volunteered the canteen facilities, which did no harm at all to my SOE scorecard. Marks & Spencer's greatest asset always was its timing.

I was also interviewed, skilfully and inscrutably, by Captain Dansey, the head of Codes, who indicated that he would think me over. A week later I signed the Official Secrets Act and was told to report to Dansey at nine in the morning.

On that last day of my innocence the personnel officer beamingly confirmed that I was to receive the equivalent of a second lieutenant's pay and then added, as tactfully as he was able, that my employment would be subject to review at the end of the month.

He was wrong again.

It was to be subject to review at the end of one day.

SOE's code department and teleprinter rooms occupied the whole of a mews building at the back of Michael House and I had my first glimpse of the wonders of Danseyland when an armed escort took me on an intensive route march to the captain's office, where I was handed over like a parcel of dubious content in exchange for an official receipt. This was standard SOE procedure for those who had yet to be issued with passes.

The sharp-eyed captain and his jovial deputy, Lieutenant Owen, explained that SOE's main function was dropping agents into Europe, and that my job would be to 'keep an eye on the security of their codes'. They then decided to test their new boy's ability. I was handed a message in code, put into an adjacent room and left there to break it. I knew from the little they had said about the code that it was one of the first Bedford had taught us to crack. If I risked no short cuts I should reach the code's jugular by the end of the day.

Dansey came in half an hour later to see if I'd finished but I was still taking a frequency count (this is the cryptographic equivalent of feeling a pulse). He looked at me with a hint of disappointment -- then smiled encouragingly and went out. It was then ten o'clock.

An hour later he was back again. The code's pulse was regular. Dansey's wasn't. 'Marks,' he said softly.


'Do you know how long it took my girls to crack that code?...twenty minutes.'

'Sir, it takes me thirty just to clean my glasses.'

I hoped he was joking. He closed the door behind him and I knew that he wasn't.

At one o'clock Lieutenant Owen put his head round the door, watched the poor struggler as long as he could bear to, and said I was free to go to lunch if I wished. I didn't.

At four o'clock a bespectacled young lady put some tea on my desk. She departed hastily with each eye laughing at a different joke.

At a quarter to five I knocked on the door of Dansey's office and put the decoded message in front of him.

Dansey and Owen sat in silence. They were in mourning for their judgement. I knew I had failed and hoped it wouldn't prevent them from giving someone competent a chance. I thanked my ex-bosses for my tea and turned to go.

'Leave the code here, please.'

'What code, sir?'

Dansey closed his eyes but they continued glaring. 'The code you broke it with!'

'You didn't give me one, sir.'

'What the hell are you talking about? How did you decode that message if I didn't give you one?'

'You told me to break it, sir.'

He was one of the few people who could look efficient with his mouth open. 'You mean you broke it,' he said, as if referring to his heart, 'without a code?'

I had always understood that was what breaking a code meant, but this was no time for semantics. 'How was I expected to do it, sir?'

'The way the girls do, with all the bumph in front of them. A straightforward job of decoding, that's all I was after! So we could test your speed. And compare it with theirs.'

'You mean, sir -- that SOE is actually using this code?'

'We were,' said Owen. 'We have others now.'

They looked at each other. Something seemed to occur to them simultaneously. They operated like two ends of a teleprinter.

'Come with us, Marks.'

The three of us crowded into my workroom, which by now resembled an indoor tobacco plantation. Dansey didn't smoke. After a few moments of intensive rummaging he lifted a pyramid of papers and pointed to a blue card with a code typed on it in capital letters. He smiled as he held it up. His efficiency was vindicated.

I walked up to him till I was level with the pips on his shoulder. I had a request to make and, for the first time in far too long, it wasn't wholly self-interested. 'May I see those other codes, sir?'

The Baker Street code room, which Dansey and Owen ran with an efficiency and precision 'Uncle Simon' would have envied, was essentially a main-line code room. Its function was to communicate with embassies and base stations around the world using code-books and one-time pads which provided the highest possible level of security and were cryptographically unbreakable even by Tiltman. It was the luxury end of the business.

The agents in the field had to use their codes in conditions of difficulty and danger which were unique in the history of coding. Their traffic was handled in that main-line code room by anyone available to do it. The volume of main-line traffic allowed no specialization. Each girl had to be a multi-purpose coder, able in theory to switch from main-line traffic to agents' at a moment's notice, though the system called for very different aptitudes, attitudes and disciplines.

The responsibility for both main-line and agents' codes was vested in Dansey and Owen. Each of them had an asset which was rare in SOE -- the ability to know what he was best at doing. They had repeatedly tried to persuade SOE that agents' traffic needed a cryptographer to supervise it -- and permission had finally been given to add one to the staff. His brief, as SOE conceived it, was a simple one. All he would be required to do was 'keep an eye on the security of agents' traffic' -- and perhaps break one or two of the indecipherable messages which poured in from the field.

The agents were using poems for their codes. Or famous quotations. Or anything they could easily remember. This concept of clandestine coding had been adopted by SOE because of a theory, traditional in Intelligence, that if an agent were caught and searched it was better security if his code were in his bead. I had a gut feeling right from the start that this theory was wrong, and hoped that whoever advised SOE that the poem-code was suitable for agents would try performing its paper-gymnastics in the field.

The slightest mistake in the coding, a second's lapse of concentration, would render the entire message indecipherable. Frequently as much as 20 per cent of SOE's traffic could not be decoded due to agents' errors.

Whenever SOE received an indecipherable the agent responsible was instructed to re-encode it and have it ready for his next transmission.

I was prepared to fight this malpractice by whatever means I could.

If some shit-scared wireless operator, surrounded by direction-finding cars which were after him like sniffer dogs, who lacked electric light to code by or squared paper to code on -- if that agent hadn't the right to make mistakes in his coding without being ordered to do the whole job again at the risk of his life, then we hadn't the right to call ourselves a coding department.

Surely the answer was simple? Squads of girls must be specially trained to break agents' indecipherables. Records must be kept of the mistakes agents made in training -- they might be repeating them in the field. SOE would need more coders -- and would have to compete for them in the far from open market. There must be no such thing as an agent's indecipherable.

Dansey didn't disagree with any of this. He simply pointed out a major obstacle of which I knew nothing. The name of that obstacle was Chain of Command.

All SOE's communications were under the control of the Signals directorate. Since these communications were worldwide, this empire-builder's paradise embraced main-line and agents' codes, ali wireless stations, all wireless training schools, all wireless equipment -- and one or two research establishments which no one had found time to visit.

The head of the Signals conglomerate, Colonel Ozanne, was a problem to which no solution compatible with law was remotely in sight. A one-man obstacle course, the colonel was opposed to any kind of change except in his rank. He elected to concentrate on main-line communications whilst taking an 'overall view' of everything else, though he often had difficulty in focusing his viewfinder, especially after lunch. His second in command, Colonel George Pollock, controlled the wireless stations, the training schools and agents' communications generally. This hierarchical structure put Dansey in the delicate position of being answerable to Ozanne for main-line codes and to Pollock for agents'.

Pollock's peacetime occupation posed problems of a special kind. He was a highly successful barrister who'd been well on his way to becoming a judge, and he used the Signals directorate as an extension of his chambers. All Dansey's requests were subjected to litigation and the verdict invariably went against him. Though Dansey never hesitated to stand up and be frequency-counted, he was in every respect outranked. The colonel disliked the untidy conveyancing which placed Dansey under his command but not under his control and had made several attempts to take agents' codes away from him, the last of which had almost succeeded.

Dansey warned me that I must do nothing which would give him an excuse to try again. 'In fact,' he said, 'you must go very carefully until your appointment is confirmed. And, after that, old boy -- you must go more carefully still.'

I managed to comply for two whole weeks.

Even SOE knew that for security reasons all messages to and from the field had to be at least 200 letters long -- one more dangerous disadvantage of the poem-code. The country section officers who originated messages had acquired the appalling habit of sending the same text to as many as a dozen different agents with only marginal changes of phrasing.

The poem-code simply couldn't stand up to these mass-produced texts. If the enemy broke one agent's messages they would know what to look for in their other intercepts -- it would be an anagrammer's delight.

I made my first contact with Buckmaster of the French section, Hardy Amies of the Belgian, Hollingsworth of the Danish, Blizzard of the Dutch, Wilson of the Norwegian and Piquet-Wicks of another French section, though I wasn't yet sure why there had to be two. I asked them to paraphrase their messages and free their language whenever possible, and mistook their acquiescence for security-mindedness instead of the quickest way to get me off the telephone.

The next time I held out the begging-bowl on behalf of the infirm poem-code was for a very different ailment, and the remedy was even less to their liking.

To encode a message an agent had to choose five words at random from his poem and give each letter of these words a number. He then used these numbers to jumble and juxtapose his clear text. To let his Home Station know which five words he had chosen, he inserted an indicator-group at the beginning of his message. But if one message was broken -- just one -- the enemy cryptographers could mathematically reconstruct those five words and would at once try to identify their source.

Amongst SOE's best-sellers were Shakespeare, Keats, Tennyson, Molière, Racine, Rabelais, Poe and the Bible.

One agent had been allowed to use the National Anthem, the only verses which he claimed to remember: suppose the enemy broke one of his messages and the five words he'd encoded it on were 'our', 'gracious', 'him', 'victorious', 'send', then God save the agent. They could sing the rest of the code themselves and read all his future traffic without breaking another message.

Even works less familiar to the Germans than the National Anthem -- the Lord's Prayer perhaps -- would cause them no problems. Reference books are jackboots when used by cryptographers. But if our future poem-codes were original compositions written by members of SOE, no reference books would be of the slightest help in tracing them. Not even Marks & Co.'s.

It would make it slightly more difficult for SOE's messages to be read like daily newspapers if we started a Baker Street poets' corner.

I hadn't thought that writing poetry would be my contribution to Hitler's downfall, but it would at least prevent the Germans from using our traffic for their higher education. Striding up and down the corridors like the Poet Laureate of Signals, I did what I could to make my poems easy to memorize, less easy to anticipate, but I was obliged to turn to the country sections for help with their respective languages. I again telephoned Messrs Buckmaster, Amies, Hollingsworth, Blizzard, Wilson and Piquet-Wicks and asked if they would kindly write some poetry for me in their respective languages.

Rumour began to spread that there was an outbreak of insanity in the Signals directorate.

It was well founded. Agents were making so many mistakes in their coding that breaking their indecipherables single-handed against the clock was like being the only doctor in a hospital full of terminal patients. And the biggest indecipherable of all was SOE itself.

Formal acceptance into the organization had brought me no closer to understanding it. All it had produced was a pass of my own which I could rarely find, and a desk in Owen's office which I rarely left. Although the code room was only a few yards away, I seldom visited it as main-line codes were none of my business. All maimed agents' messages were brought in to me as the girls had neither the time nor the training to mend the fractures.

The prospect of ever being able to form a code-breaking team seemed even more remote when Dansey's foreboding hardened into fact. Ozanne transferred all agents' traffic to the wireless station at Grendon Underwood. The coding was to be done by groups of FANYs (First Aid Nursing Yeomanry). The takeover was to be in August, only a few weeks away. Dansey would still be in charge of agents' codes -- but this could be changed at the flick of a mood-swing. He warned me not to visit Station 53 without the approval of the Gauleiter of Signals.

While grim power-struggles were raging throughout every directorate in SOE, I was engaged in a still grimmer one with Edgar Allan Poe.

He was the favourite author of an officer on Buckmaster's staff named Nick Bodington, who went backwards and forwards to France as if he had a private ferry. For this trip's traffic he'd chosen an extract from 'The Raven'. Bodington's message was indecipherable and I'd been impaled on the bloody bird's beak for six consecutive hours.

The passage Bodington had chosen was:

While I nodded, nearly napping, suddenly there came a tapping,

As of someone gently rapping, rapping on my chamber door...

If the indicator-group were correct, the five words he'd encoded the message on were: 'came', 'chamber', 'my', 'rapping', 'door'. When I tried decoding it on these five, all that emerged was the Raven's cackle.

Some 3,000 attempts later I discovered that the indicator was correct and the coding perfect. All Bodington had done was omit a 'p' from 'rapping', which turned it into 'raping' and screwed the lot of us.

The worst part of these indecipherables was the time element. If an agent had a schedule for six o'clock, his message would have to be broken by then or his section head would insist that he repeated it. I didn't always manage to beat the clock, but only once gave up trying.

I had been working for two days on an indecipherable from Norway contributed by an agent called Einar Skinnarland. There was something very peculiar about Skinnarland's traffic. He gave some of his messages to a wireless operator to be transmitted in the normal way (SOE was blasé enough to regard wireless traffic as normal) -- but, for reasons which the Norwegian section refused to divulge, at any rate to me, most of his traffic was smuggled into Sweden by courier and re-routed to London by cable or diplomatic bag. He had already sent one indecipherable, and the usually imperturbable Wilson had stressed to me that he must know its contents within the hour. An hour in coding terms is only a paranoid minute. I needed to know what was so special about Skinnarland's traffic -- but Wilson rang off abruptly to take another call.

That first indecipherable of Skinnarland's had been a warming-up present from him to me and had proved no more troublesome than an undone shoelace. Wilson expected the new one to be cracked as easily. But Skinnarland had had the better of our two-day duel, and five minutes before his operator's schedule I just had to get away from the thousands of failed attempts which littered my desk. I strolled upstairs to the teleprinter room to listen to the healthy chatter of Dansey's main-line codes. Suddenly I knew what Skinnarland had done and saw that, if I took a short cut and drew together several columns of his message, I would get the word 'sentries' in one line with the word 'Vermok' immediately beneath it. Taking an even shorter cut to the code room by falling down the stairs, I contacted Station 53 on the direct line.

The operator was still on the air, about to be asked to repeat the message. I told the signalmaster to cancel the instruction and send the Morse equivalent of 'Piss off fast.'

Breaking that indecipherable to the applause of my public meant far more to me at the time than that factory in remotest Vermok which Skinnarland had described in minutest detail. The rest of SOE remained equally remote.

The most distinguished visitors to our mews stronghold were the night duty officers who collected the confidential waste and the ladies who pushed around the teatrolley twice a day like sisters of mercy. But one afternoon I was struggling with yet another indecipherable from Skinnarland, who was rapidly becoming my least favourite agent, when I heard an uncommonly authoritative, disconcertingly purposeful barrage of footsteps coming our way. A moment later an RAF officer strode into the room and commandeered it without a word being spoken. I had never seen anger of such quality and substance, power and purpose as this man projected. It should have been weighed by the pound and sold as an example.

I forgot about Skinnarland as he advanced on my startled superior, making no attempt to conceal his repugnance at a pink slip (an internal message to Station 53) which was clutched in his outstretched hand.

'Who's responsible for sending this?'

'He is.'

The flight lieutenant transferred his attention to me, and his first question set the tone of our encounter: 'Who the devil are you?'

Every officer in SOE was allocated a symbol for use in correspondence; Dansey's was DYC, Owen's DYC/O. At last I had a chance to use mine. 'DYC/M,' I said, quoting it with relish.

'Tony had a sked at nine tonight. You've bloody cancelled it! Why?'

Tony was an agent stranded in France with the Gestapo searching for him. A Lysander was standing by to pick him up, but his message giving map references had been indecipherable. He was due to repeat it.

'I cancelled it,' I said, 'because an hour ago we broke it after three thousand, one hundred and fifty-four attempts.'

Skinnarland's indecipherable whispered something to me in its coding sleep.

'How did you break it?'

A word was forming which could be 'mountain'.

'How did you break it?'

It was 'mountain'.

'By guess and by God,' I said without looking up.

'Really, DYC/M? And which were you?'

'Barren mountain' -- I hoped it would make sense to Wilson.

'Flight Lieutenant, if you come back in a year's time I may have finished this bugger, and I'll be glad to answer all your questions.'

'Very well, DYC/M. I'll look in again the Christmas after next, if you haven't won the war by then.'

He closed the hangar door behind him. I could still feel him looking at me.

'Who was that sod?'

'Didn't you know? That's Yeo-Thomas. Our Tommy!...he's quite a character.'

I didn't realize it at the time but 'quite a character' was even more of an understatement than 84's tax returns.

Copyright © 1998 by Leo Marks

Chapter Two

The Pilot Light

SOE's security checks were so insecure that I thought the real ones were being withheld from me. Their function was to tell us whether an agent was coding under duress. To convey this to us without the enemy being aware of it, he was required to insert various dummy letters in the body of each message -- and their absence or alteration in any way was supposed to alert us immediately to his capture. As an additional 'precaution' he was instructed to make deliberate spelling mistakes at prearranged spots. The whole concept had all the validity of a child's excuses for staying up late, with none of the imagination. It took no account of the possibility of an agent's code being broken or tortured out of him, when the Gestapo would be in a position to work out the security checks for themselves. Nor did it make any allowances for Morse mutilation, which frequently garbled so much of the text that it was impossible to tell whether the security checks -- for what little they were worth -- were present.

I had already been puzzled by the traffic of a Dutch agent named Abor who'd been dropped into Holland in March. He'd sent a string of properly encoded messages -- yet all of them were marked security checks omitted, and he'd clearly made no attempt to use them from the moment he'd arrived. When I raised this with N (the Dutch) section I was told there was nothing to worry about -- 'The whole thing has been looked into; the agent's all right.' There was so much else to worry about that I put this enigma on one side.

I had discovered that through no fault of anyone's (a rare situation in SOE) an agent could have a long period of waiting between leaving his training school and being dispatched to the field. His 'refresher course in coding' was left to his original training officer, if he wasn't too busy, or to his country section briefing officer, if he knew how to code. In case this accounted for the high rate of indecipherables, I raised a mortgage, on my confidence and offered to brief agents myself.

Word spread quickly that someone in SOE was volunteering for extra labour, and my panel practice came of age when Buckmaster asked me to brief two F section agents named, respectively, Peter and Paul. Feeling like a pill-pusher with Messianic pretensions, I reported to F section's Orchard Court flat to meet my first pupils.

Peter's surname was Churchill -- and thanks to a briefing from Owen I knew far more about him than he about me. This slender man, coiled in his chair like an exclamation mark with a moustache, had got into the habit of slipping across to the South of France, usually by submarine and canoe, and staying there as long as Buckmaster and circumstances would permit. I had no idea what Peter's new mission was but he seemed no more concerned about it than a day-tripper with some business on the side. The prospect of the South of France had put him in a holiday mood and it was with some reluctance that he interrupted it for a 'spot of coding'.

Within the next five minutes he made as many mistakes. I asked him to stop, which he did with alacrity. I knew that Peter had left Cambridge with a degree in modern languages and the reputation of being one of the finest ice-hockey blues the university had produced. Hoping to establish common ground, I discussed the 'language of coding', the rules of its 'grammar', the nature of its 'syntax'. I told him that he 'spoke coding' with a bloody awful accent which would give him away, and then switched metaphors. We chose five words of his poem and lined them up as if they were members of his hockey team, and I asked him for both our sakes to remember where the goal was. He skated through two messages without one false pass and was about to try a third when he received a phone call from Buckmaster.

'Yes, Maurice? who?...his name's what?...(I was sure he could hear but being difficult was a sport for which he'd also won a blue) but Maurice, I'm still having a hockey lesson from Marks...all right then, if I must.'

He apologised for having to leave at half-time, promised not to get sent off for foul coding, and hurried away.

I went next door and met my first frightened agent.

When Paul and I shook hands they needed galoshes. He seemed even more of a refugee from the civil war of adolescence than I was. He was English but spoke French like a native and was due to be dropped into France in a few nights' time. He showed me a message he'd been working on. He'd found a way to go wrong which not even Skinnarland had thought of. He'd started by encoding his message quite normally, then switched to the process reserved for decoding it -- which was like straddling two escalators going in opposite directions. This was after eight weeks of training. I took him through the whole system from beginning to end and he understood it perfectly, which was even more worrying.

He suddenly asked what would happen if he made 'a bit of a mistake' and sent us a message which we couldn't decode.

I didn't want him to know that he'd be dependent on me. I improvised a little and told him that we had a team of girls who'd been specially trained to break indecipherable messages. Each girl, I said, 'adopted' an agent so that if he made a mistake or two in his messages, she'd be familiar with his coding style. I then asked him to run through his poem for me and took out his code-card to check the wording. He shyly admitted that Tennyson's 'In Memoriam' was his favourite poem, and that he was grateful to his instructor for allowing him to use it. He added that he was afraid someone else might have picked it first.

He was silent for a few moments and then whispered the words -- I wasn't sure to whom:

Be near me when my light is low,

When the blood creeps, and the nerves prick

And tingle; and the heart is sick,

And all the wheels of being slow.

Be near me when the sensuous frame

Is rack'd with pangs that conquer trust;

And time, a maniac scattering dust,

And life, a fury slinging flame.

Be near me when my faith is dry,

And men the flies of latter spring,

That lay their eggs, and sting and sing

And weave their petty cells and die.

Be near me when I fade away,

To point the term of human strife,

And on the low dark verge of life

The twilight of eternal day.

I was careful to keep looking at the code-card. There was nothing more that I could say to him. But there was one thing that I could do.

Without telling anyone, I ordered a car and went to meet the coders of Grendon.

Every girl in the code room at Station 53 could have walked out of her job at a month's notice. They were all in the FANY, a volunteer organization whose members could resign at will. The average age of these girls was twenty, though there was a sprinkling amongst them of watchful matriarchs, and most of them had been selected as coders oil an arbitrary basis because they happened to be available when coders were wanted. After the briefest training they were dispatched to one of the most secret establishments in England and left to get on with it. They were never allowed to meet the agents whose traffic they handled and who were only code-names to them. The Gestapo had no more reality for these girls than when they'd joined the FANY.

As I opened the door of the lecture room, forty of them stood to attention. I wasn't sure how to get them to sit down again and made a vaguely royal gesture which had no immediate effect. I walked up to the blackboard at the far end of the room, wrote out a message in code which I hoped was legible and turned to face them.

It was the first time I'd ever given a lecture except to the one or two girls I'd taken out. I wasn't prepared for their impact en masse.

I spotted two gigglers at the back of the room and talked only to them for the first five minutes -- about agents in the field and the risks they took to send messages to us. I quoted verbatim from a telegram Dansey had shown me only two nights ago about a Yugoslav partisan, eighteen years old, who had been caught with a wireless transmitter, had refused to betray the organizer whose messages he was sending and was eventually taken to the mortuary 'no longer recognizable as a human being'. They didn't handle Yugoslav traffic. There was a sudden urgency in that room to handle the Gestapo.

I asked them to help break the message on the blackboard as if they were the Gestapo; I showed them what enemy cryptographers would look for if they had intercepted the message. I began to anagram and asked them to join in. They were shy at first -- but soon suggestions were being called out from all round the room and those from 'the gigglers' were amongst the brightest. I reserved them for Paul.

It was oversimplified, of course, but it gave them the 'feel' of code-breaking, and the principles they were shown were absolutely valid.

I let them finish the message themselves. The clear-text read: 'From the coders of Grendon to the agents of SOE. THERE SHALL BE NO SUCH THING AS AN INDECIPHERABLE MESSAGE.'

I knew I would be overloading the girls if I continued but I couldn't resist it. I wanted them to see how the enemy would now mathematically reconstruct the five words on which the message had been encoded.

It took them twenty minutes to recover those words but no one could identify the rest of the poem. I spoke it to them in full: '"Be near me when my light is low..."'

Two days later they sent me a message on the teleprinter: 'WE HAVE BROKEN OUR FIRST INDECIPHERABLE. THE CODERS OF GRENDON.'

I sent them a message of congratulations on behalf of all agents. The pilot light in SOE's code room had started to burn.

Copyright © 1998 by Leo Marks

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What People are saying about this

Martin Scorsese
A mesmerizing account of World War II as fought on the home front in Great Britain by the ingenious codemakers whose work determined the life and death of the Allied agents in occupied Europe. Leo Marks, a brilliant cryptographer, is a masterful and passionate storyteller. I was immediately swept into his secret world of codes and "undecipherables," trying at times (without success) to unravel the puzzles myself, and found it difficult to put down the book until the drama had come to an end.

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Between Silk and Cyanide: A Codemaker's War, 1941-1945 3.8 out of 5 based on 0 ratings. 10 reviews.
Guest More than 1 year ago
This is a very detailed account of one secret codes department of British Intellegence Service during World War Two. Leo Marks, fresh out of school, was hired to head up this department, and he obviously knows his subject extremely well. All names, dates, and events are factual, and no punches are pulled. I enjoyed every one of the 600 pages.
Anonymous More than 1 year ago
Anonymous More than 1 year ago
I thoroughly enjoyed this book. It is the story of a young man at the outbreak of WWII who intends to become a codebreaker and ends up at SOE ensuring the security (and readability) of codes used by covert operatives in Europe (They are all hand codes used in the field, so don't expect anything like Enigma). It includes several interesting stories of the covert operatives he meets and bosses he has to deal with. It makes fascinating reading and I couldn't put it down! My only reason for giving four rather than five stars is that the Nook version has several typos, some of the tables are not well formated and the pictures have been removed. It is nonetheless quite readable and worth the read.
Anonymous More than 1 year ago
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Anonymous More than 1 year ago
The book is well done except that it assumed you new more math than I actually did and I believe it could be said of more readers than just I. Very informational IF you had some background or knowledge of the workings of British government.
Anonymous More than 1 year ago
Guest More than 1 year ago
It's as simple as my headline says - buy it. I've read it 5 times now, and it's one of my all time favorite books! Aside from being a brilliant account of Leo Marks' brilliance as a cryptographer and SoE's work during the war, it is also brilliantly written. Marks intellekt and litteral skill really shines through in his language and his humor. I can recommend this book to literraly ANYONE. It doesn't really matter if you like math and codes and stuff. Hell, you don't really need to care about WWII. What this book is about is not codes, and it's not even Marks himselft - it's about the people who fought the germans in every way they could. It's about the heroes of WWII who risked their lives, and frequently lost it, in the service of a greater good. Marks really makes the people he met come alive, and THAT is what makes this book outstanding. I dare you to not be touched during this book. Read it.
Guest More than 1 year ago
This is an amazing book. There are a lot of increadible stories from the seccond World War but very rarely do the great stories fall into the hands of great writers. Marks is in just that position. We all know the stories of Bletchley Park, the Enigma machine and Alan Turing (or if we don't we darn well should) but this is a rarely heard perspective of the other side of cryptography. I couldn't put this book down. A landmark in the history of code making and breaking. I've probably bought about five copies of this for the war story enthusiasts in my life and every one of them has been impressed.
Guest More than 1 year ago
This supposedly insightful look into cytography during World War I was horribly untolerable to everyone except the author. It's appeal stretches only as far as one cytographer to another. It's lack of actual insight into the war was depressing. No specific details were mentioned. This is definitely not a recommended book on my list.