The Codebreakers: Who Worked at Bletchley Park During World War Two?

The Codebreakers: Who Worked at Bletchley Park During World War Two?

This article is an edited transcript of Bletchley Park: The Home of Codebreakers on Dan Snow’s Our Site, first broadcast 24 January 2017. You can listen to the full episode below or to the full podcast for free on Acast.

By the end of the Second World War in 1945 nearly 10,000 people worked at Bletchley Park, an enormous increase on the 130-strong staff that composed the Government Code and Cypher School in 1939.

In many ways it was one of the most remarkable groups ever assembled.

Alice Loxton tracks down four female veterans who share their stories of the Second World War.

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How Bletchley utilised a huge team to industrialise codebreaking

First and foremost there was a cadre of highly talented cryptanalysts at Bletchley. These were the minds who came up with solutions to problems.

Those solutions were then taken away and industrialised – a process that required a whole separate pool of people. Not necessarily people who had Cambridge degrees. These were clever, able recruits who had a reasonable high school education.

They came in, in their thousands, and were often given very dull jobs to do. But they were part of a chain that allowed thousands of messages to be decrypted and understood every day.

A statue of Alan Turing, one of Bletchley Park’s leading mathematicians.

The officials behind Bletchley Park recognised that it’s not good enough just to have geniuses like Alan Turing, you also need people who can enable that cleverness. The combination of these two types of people is what really made Bletchley a success.

Not only were they responding to the different codes that Britain’s enemies were using, they were also devising ways to break those codes on an industrial scale. This was absolutely key – reading one enemy message doesn’t really help you but reading a thousand enemy messages gives you a massive advantage.

Such demands meant that Bletchley was in a constant race to build more facilities, to hire more staff, to train people and to generally expand the operation, all the time knowing that if the Germans made one slight change to what they were doing, the whole plan could collapse like a house of cards.

Not only were they responding to the different codes that Britain’s enemies were using, they were also devising ways to break those codes on an industrial scale.

Such crushing collapses certainly weren’t unheard of. One team spent most of the 1930s building the complete Italian naval codebook, only for it to be scrapped in 1940 when Italy joined the war. That team, some of whom had been at it for ten years, simply had to start again.

The stamina and the determination to take hits like that and just carry on was at the heart of Bletchley’s success.

Join Dan Snow on an exclusive tour of the house and grounds, as well as the little known but all-important cottages that surround Bletchley Park.

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What is the legacy of Bletchley Park?

A lot of people talk about the legacy of Bletchley Park in terms of electronic devices. They might look at the Bombe machine or at Colossus, which was an early form of electronic computer, and decide that Bletchley’s lasting impact was technological.

Such a conclusion misses the point though. Bletchley Park – all 10,000 people, from the boffins to the tea ladies – was essentially a big computer.

A reconstruction of one of the Bletchley Park Colossus Machines, the world’s first programmable, digital, electronic, computing devices.

Data, in terms of messages, was put in at one end and that information was processed in incredibly sophisticated ways, often by people sitting in a room and doing something very dull, sometimes by a machine, sometimes by being written on index cards. And out of the other end came intelligence and decrypted information.

Bletchley showed us how to organise people to get a job done and how to process data in large volumes.

It’s that organisation, not just of machines but also of people and of talent, that produced a result. This is why today’s big companies, not only IT companies but corporations of every variety, owe a debt to Bletchley Park.

Bletchley showed us how to organise people to get a job done and how to process data in large volumes. These lessons were much more to do with humans than machines.


The Women Codebreakers of Bletchley Park

For years, the efforts of thousands of codebreakers working in small huts in the grounds of a large mansion somewhere in Buckinghamshire was kept as one of the biggest secrets of the Second World War. The most famous figure is the great Alan Turing. Without him, the &sbquoÄòbombe&sbquoÄô machine would not exist and the Allies would have remained unable to read German Naval messages. Yet, it seems to have gone largely unnoticed that 80% of the 9,000 staff working at Bletchley Park were, in fact, women. These women were clever in their own right, and worked just as tirelessly to crack the German Enigma codes. It is believed that the efforts of both Alun Turing and these women helped to shorten the war by at least two years and saved millions of lives.

The story starts with eccentric lead male codebreaker Dillwyn &sbquoÄúDilly&sbquoÄù Knox, who requested an all-female team to work with. These ladies would soon receive the nickname &sbquoÄúDilly&sbquoÄôs girls&sbquoÄù. It was this all-female team who would break the Abwher Engima Machine between October and December 1941 and give the Allies control over the German spy network in Britain. The Allies were now able to feed misinformation back to Germany on military movements, such as the attack on D-Day. Dilly Knox with his all-female team gave the Allies the military advantage and helped win the war.

Working at Bletchley Park was well-paid with food, accommodation and uniform provided. Most of the women hired were young and straight out of college or university. All were brilliant problem-solvers or mathematicians. The Bletchley Girls stayed with local families whilst at Bletchley, or slept in bunks within the small huts on the park grounds. Those who arrived at the large mansion in the middle of nowhere had little knowledge of what they were going to be doing and each person was made to sign the Official Secrets Act immediately upon arrival. The Act required all-out secrecy of what the girls were doing at Bletchley Park for the next thirty years. Secrecy would come to dictate their lives even during the war. It was not just family, friends and boyfriends kept in the dark, or lied to, but colleagues as well. Many women never knew what the women in the next hut just a few yards away were doing, and work was never discussed when the girls were off duty. The consequences of doing so cost them their jobs and endanger the whole operation. Many of the girls were grateful for the opportunity to be at Bletchley Park doing what they were doing and support the war effort.

Joan Clarke studied mathematics at Newnham College, Cambridge and had completed Part I & II of her Mathematics Tripos by 1939. She completed Part III in 1940. It was her Geometry supervisor, Gordon Welchman, who recruited her for the Government Code & Cipher School in June 1940. From there, Joan Clarke became one of the few recognised women codebreakers at Bletchley Park &ndash and one of two women to hold leadership roles.

Margaret Rock was 36 years old when arrived at Bletchley Park on 15th April 1940, making her older than most of the girls recruited. She was a graduate mathematician and statistician, which made her an ideal recruit. It was towards the end of 1941 that Margaret broke the Abwehr Enigma machine code alongside her colleague, Mavis Lever. Margaret would publish Dear Code Breaker many years later. The book would give a unique insight into her daily life.

Mavis Lever worked for the Ministry of Economic Welfare at the Foreign Office after studying German Literature at the University College London. It was her logical thinking that got her noticed and in June 1940 she found herself at Bletchley Park.

It seems ironic that in a world where women were thought to be incapable, the codebreakers of Bletchley Park helped to end the war. Few of these women were formally recognised as cryptanalysts at the time, besides them working at the same level as their male peers. With the secrecy lifted in 1975, many women have been able to talk about their experiences. Sadly, though, it only seems to be recently that we are listening to these fascinating stories about the Bletchley Girls and their part in the war.

Bletchley Park itself is open to visitors all year round and well worth exploring!


Photos Of WWII Codecrackers Go On Sale At Bletchley Park

Rare pictures of intelligence surveillance operations carried out during World War Two have been released by the mansion where top wartime codecrackers worked.

Bletchley Park, which was known as Station X during hostilities, has issued a collection of limited edition fine art prints signed by five figures behind the covert efforts which decrypted enemy plans, playing a vital part in conflicts such as the Battle of the Atlantic.

They include John Herivel, whose Herivel Tip was instrumental in intercepting the German Enigma machine’s operations in 1940, and Mavis Batey, who had a key role in the allied naval victory at the Battle of Cape Matapan. Two former Cambridge mathematicians, Keith Batey and Oliver Lawn, also contribute, alongside Lawn’s wife, Sheila, a linguist recruited from Aberdeen University.

The revealing photos are on sale to members of the public as part of fundraising efforts for Bletchley Park

Secret service security prohibited cameras from being used at the site during the campaign, but the Government Communications Headquarters has given special permission for the images to be produced as part of fundraising efforts in aid of the park.

Simon Greenish, chief executive of the Bletchley Park Trust, said: “These prints offer an opportunity to buy a unique piece of history, and will help to ensure that the legacy of the wartime Codebreakers at the home of computing is not forgotten.”


How the American Women Codebreakers of WWII Helped Win the War

It was a woman code breaker who, in 1945, became the first American to learn that World War II had officially ended.

The Army and Navy's code breakers had avidly followed messages leading up to that fateful day. Nazi Germany had already surrendered to the Allies, and tantalizing hints from the Japanese suggested that this bloody chapter of history might soon come to an end. But when U.S. Army intelligence intercepted the Japanese transmission to the neutral Swiss agreeing to an unconditional surrender, the task fell to Virginia D. Aderholt to decipher and translate it.

Head of one of the Army's language units, Aderholt was a master at the cipher the Japanese used to transmit the message—teams crowded around her as she worked. After the Swiss confirmed Japanese intent, the statement was hurried into the hands of President Harry S. Truman. And on the warm summer evening of August 14, 1945, he made a much-anticipated announcement: World War II was finally over.

Throngs of Americans took to the streets to celebrate, cheering, dancing, crying, tossing newspaper confetti into the air. Since that day, many of the men and women who helped hasten its arrival have been celebrated in books, movies and documentaries. But Aderholt is among a group that has largely gone unnoticed for their wartime achievements.

She is just one in upwards of 10,000 American women codebreakers who worked behind the scenes of WWII, keeping up with the conveyor belt of wartime communications and intercepts. These women continually broke the ever-changing and increasingly complex systems used by the Axis Powers to shroud their messages in secrecy, providing vital intelligence to the U.S. Army and Navy that allowed them to not only keep many American troops out of harm's way but ensure the country emerged from war victorious.

The information they provided allowed the Allied forces to sink enemy supply ships, gun down the plane of Isoroku Yamamoto, the architect of Pearl Harbor, and even help orchestrate the invasion of Normandy. During the later years of war, the intelligence community was supplying more information on the location of enemy ships than American servicemen could keep up with.

"The recruitment of these American women—and the fact that women were behind some of the most significant individual code-breaking triumphs of the war—was one of the best-kept secrets of the conflict," writes Liza Mundy in her new book Code Girls, which finally gives due to the courageous women who worked in the wartime intelligence community.

Some of these women went on to hold high-ranking positions—several even outranking their military husbands. Yet to this day, many of their families and friends never knew the instrumental role they played in protecting American lives.

The Navy women worked in three shifts a day constructing the many gears and gadgets that make up the Bombes—the machines used to decrypt the German Enigma cipher. A separate unit of women were tasked with the challenging job of running the finicky machines. (National Security Agency) The Army had an African-American codebreaking unit, but little is known about these women. Led by William Coffee, shown here in the middle of the image, the group remained strictly segregated from the rest of the codebreaking efforts. They were tasked with monitoring enciphered communications of companies and banks to track business interactions of Axis powers. (National Security Agency) A former private school for women, Arlington Hall housed the Army codebreaking operations during WWII through most of the Cold War. (National Security Agency) Adolf Hiitler shakes the hand of Baron Hiroshi Oshima, a Japanese diplomat and Imperial Army General. Oshima commonly used the Purple cipher to transmit detailed reports, including many comprehensive Nazi plans. By cracking Purple, the U.S. gained insight into many of the Axis strategies, which was instrumental in the Allies' preparation for the invasion of Normandy. (National Security Agency)

Mundy happened upon the story while her husband was reading Robert Louis Benson and Michael Warner's book on the Venona project, a U.S. code-breaking unit focused on Russian intelligence during WWII and the Cold War. One particular detail of Venona surprised Mundy: the project was mostly women.

Curiosity piqued, she began digging into the topic, heading to the National Cryptologic Museum and the National Archives. "I didn't realize at that point that the Russian codebreaking women were just a tiny part of a much larger story," she says. "I thought I would spend a week in the archives. Instead, I spent months."

Mundy, a New York Times bestselling author and journalist with bylines in The AtlanticThe Washington Post and elsewhere, dug through thousands of boxes of records, scouring countless rosters, memos and other paper ephemera. She filed declassification reviews, which turned up even more materials. "It turned out that there was a wonderful record out there, it just had to be pieced together," she says.

Mundy even tracked down and interviewed 20 of the codebreakers themselves, but for some it required a bit of cajoling. During the war, it was continually drilled into them that "loose lips sink ships," she says. And to this day, the women took their vows of secrecy seriously—never expecting to receive public credit for their achievements. Though many of the men's tales have leaked out over the years, "the women kept mum and sat tight," she says.

"I would have to say to them, 'Look, here are all these books that have been written about it,'" Mundy recalls. "The NSA says it's okay to talk the NSA would like you to talk," she would tell them. Eventually they opened up, and stories flooded out.

Code Girls: The Untold Story of the American Women Code Breakers of World War II

A strict vow of secrecy nearly erased their efforts from history now, through dazzling research and interviews with surviving code girls, bestselling author Liza Mundy brings to life this riveting and vital story of American courage, service, and scientific accomplishment.

Before the attack on Pearl Harbor, which propelled America's entrance into the war, Army and Navy intelligence employed a couple hundred people. The intelligence field was in its infancy. The CIA didn’t yet exist and the forerunner of what would later become the NSA had just been established.  W ith war on the horizon, federal agencies were already working to recruit potential  codebreakers  and intelligence officers, but  men were also  needed for the armed forces, prepping for war. So as the agencies located suitable candidates, the men would be “gobbled up by the active militaries," Mundy says.

Many men also weren't interested in the job. At the time there was little prestige in the work the battlefield was where heroes were born. Those who worked behind the scenes could say little about their accomplishments. And the work was seen as secretarial in some ways, Mundy notes.

It wasn't until after Pearl Harbor that the real push to grow the ranks of intelligence began. In the weeks leading up to this fateful day, there was a sense of impending danger, but exactly where and when that assault would take place remained a mystery. Just days before the attack, the Japanese changed up part of their coding system. The codebreakers scrambled to crack the new intercepts—but it was too late.

Why the U.S. was caught by surprise would be hashed and rehashed over the years—from conspiracy theories to congressional hearings. But the loss emphasized the growing need for enemy intelligence. And with an increasing number of men being shipped out overseas, the government turned to an abundant resource that, due to sexist stereotypes of the day, were assumed to excel at such "boring" tasks as code breaking: women.

The Army and Navy plucked up potential recruits from across the country, many of whom were or planned to become school teachers—one of the few viable careers for educated women at the time. Sworn to secrecy, these women left their loved ones under the pretense of doing secretarial work.

Unlike the men, women code breakers initially signed onto the Army and Navy as civilians. It wasn’t until 1942 that they could officially join with many lingering inequities in pay, rank and benefits. Despite these injustices, they began arriving in Washington D.C. by the busload, and the city's population seemed to swell overnight. Exactly how many of these women contributed to wartime intelligence remains unknown but there were at least 10,000 women codebreakers that served—and "surely more," Mundy adds.

America wasn’t the only country tapping into its women during WWII. Thousands of British women worked at Bletchley Park, the famous home of England’s codebreaking unit. They served a number of roles, including operators of the complex code-breaking computers known as the Bombe machines, which deciphered the German Enigma intercepts. While the American codebreakers did assist the Allies in Europe, the majority of their work focused on the Pacific theater.

Just as women were hired to act as "computers" in astronomy to complete the rote, repetitive work, "the same was true with codebreaking," says Mundy. And though it was repetitive, the job was far from easy. There were endless numbers of code and cipher systems—often layered to provide maximum confusion.

Codebreaking entails days of starting at strings of nonsensical combinations of letters, seeking patterns in the alphabetical chaos. "With codes, you have to be prepared to work for months—for years—and fail," Mundy writes.

Over the years, the teams learned tricks to crack into the messages, like looking for the coded refrain "begin message here," which sometimes marked the start of a scrambled message. The key was to discover these "points of entry," which the code breakers could then tug at, unraveling the rest of the message like a sweater.

Many of the women excelled at the work, some showing greater persistence than the men on the teams. One particular triumph was that of junior cryptanalytic clerk Genevieve Grotjan, who was hired at age 27 by William Friedman—famed cryptanalyst who was married to the equally brilliant cryptanalyst pioneer Elizabeth Friedman.

Always a stellar student, Grotjan graduated summa cum laude from her hometown University of Buffalo in 1939. Upon graduation she hoped to go on to teach college math—but couldn’t find a university willing to hire a woman. Grotjan began working for the government calculating pensions but her scores from her math exams (required for pay raises) caught Friedman’s eye, Mundy writes.

Friedman's team was working to break the Japanese diplomatic cryptography machine dubbed Purple. When Grotjan joined on, they had already been working on it for months, forming hypothesis after hypothesis to no avail. The British had already abandoned the seemingly impossible task.

The men on the team had years or even decades of experience with codebreaking, Mundy notes. But on the afternoon of September 20, 1940 it was Grotjan who had the flash of insight that led to the break of the Purple machine. "She's a shining example of how important it was that Friedman was willing to hire women," says Mundy. "Inspiration can come from many different quarters."

The ability to read this diplomatic code allowed Allied forces to continually take the pulse of the war, giving them insight into conversations between governments collaborating with the Japanese throughout Europe.

But the work was not all smooth sailing. Shoved in crowded office buildings in the heat of the summer, the job was physically demanding. "Everybody was sweating, their dresses were plastered to their arms," Mundy says. It was also emotionally draining. "They were very aware that if they made a mistake somebody might die.”

It wasn't just intelligence on foreign ships and movements—the women were also decrypting coded communications from the American troops relaying the fate of particular vessels. "They had to live with this—with the true knowledge of what was going on in the war … and the specific knowledge of their brothers' [fates]," says Mundy. Many cracked under the pressure—both women and men.

The women also had to constantly work against public fears of their independence. As the number of military women expanded, rumors spread that they were "prostitutes in uniform," and were just there to "service the men," Mundy says. Some of the women's parents held similarly disdainful opinions about military women, not wanting their daughters to join.

Despite these indignities, the women had an influential hand in nearly every step along the path toward the Allies' victory. In the final days of war, the intelligence community was supplying information on more Japanese supply ships than the military could sink.

It wasn't a dramatic battle like Midway, but this prolonged severing of supply lines was actually what killed the most Japanese troops during the war. Some of the women regretted their role in the suffering they caused after the war’s end, Mundy writes. However, without the devoted coterie of American women school teachers reading and breaking codes day after day, the deadly battle may well have continued to drag on much longer.

Though the heroines of Code Girls were trailblazers in math, statistics and technology—fields that, to this day, are often unwelcoming to women—their careers were due, in part, to the assumption that the work was beneath the men. "It's the exact same reductive stereotyping that you see in that Google memo," says Mundy, of the note written by former Google engineer James Danmore, who argued that the underrepresentation of women in tech is the result of biology not discrimination. "You see this innate belief that men are the geniuses and women are the congenial people who do the boring work."

Mundy hopes that her book can help chip away at this damaging narrative, demonstrating how vital diversity is for problem solving. Such diversity was common during the war: women and men tackled each puzzle together.


Female codebreakers: the women of Bletchley Park

Tessa Dunlop, historian on the BBC Two series Coast, shines a light on the secret and undervalued work of the women of Bletchley Park, without whom the codebreaking successes of World War II could not have happened

This competition is now closed

Published: July 1, 2019 at 12:00 pm

This year is the 100th anniversary of GCHQ, once called the Government Code and Cipher School (GC&CS) and the brainchild behind one of World War II’s most famous institutions: Bletchley Park in Buckinghamshire.

During the war, Bletchley depended on the heft of a predominantly female workforce yet Joan Clarke, the codebreaking fiancée of Alan Turing (immortalised by Keira Knightley in the 2014 film The Imitation Game) is one of Bletchley’s very few famous woman. Britain’s codebreaking operation has been dominated by a male narrative – a star-studded cast of 20thcentury brain boxes, led by mathematician Alan Turing.

His outstanding role in the creation of the bombe machine, an electromechanical testing device essential for unravelling German Enigma encoded messages, was hugely significant. It is a feat perhaps only rivalled by that of Tommy Flowers, the engineer who designed the even more advanced Colossus, the world’s first programmable computer.

The need to outsmart one’s enemy frequently led to ground-breaking innovations during World War II, yet the women who worked at Bletchley have often been overlooked in this story because, with the exception of three or four female cryptanalysts, the vast majority of top-end codebreakers during the war were men.

The story of how girl power – often school-girl power – turned what began as an eccentric experiment into the world’s most impressive codebreaking factory is less well known, but no less important.

A question of trust

In 1938, with war on the horizon, GC&CS temporarily moved out of London, to avoid bombing raids, but by August 1939, its secret home in Bletchley Park had become permanent. Initially, this fledging operation was staffed by just 186 people. ‘Men of a professor type’, particularly mathematicians were targeted, with early recruits including Turing, Gordon Welchman and Alfred Dillwyn Knox. Their work, however, was supported by an expanding team of chiefly civilian women.

Perhaps inevitably at the beginning of the war, Establishment Britain recruited from their own when it came to Bletchley’s secret operations. The German military must never know that Britain was in the process of achieving what Hitler believed to be impossible – the decoding of Enigma. It was imperative that those selected could be trusted to keep quiet, and from kinship springs trust. Many of the first women at Bletchley Park came from ruling-class families who knew each other.

Lady Jean was a 19-year-old Scottish aristocrat and debutante. She had been tipped off about a “hush, hush mission at Bletchley Park” by her father’s friend, Lord Mountbatten. Actress Pamela Rose (née Gibson), received a letter from an “interfering godmother”. If girls’ education was rarely a priority between the wars, an upper-class focus on being accomplished and attending foreign finishing schools certainly had its advantages. Pamela’s understanding of German, for example, was deemed to be useful for filing decrypted messages.

For that work she sacrificed her first role on the West End.

From the outset, Bletchley, aka Station X, could not operate without the constant ‘traffic’ of German Enigma messages. This came from the Y Service, Bletchley’s vital other half, with its numerous listening stations intercepting German radio communications. Among the staff of the Y Service were members of the Women’s Royal Naval Service, or ‘Wrens’. One of these was 18-year-old Pat Davies (née Owtram). Assigned as a Special Duties Linguist after an intense training course, her first post on a “highly secret mission” was at Withernsea, Yorkshire. “As soon as one of the German ships came up, you wrote down exactly what you heard,” she later recalled.

A lot of what Pat remembers was the meaningless clumps of letters. “Anton, Bertha, Cesar… I always thought it was odd hearing the war all the time from the German side. The whole thing would be written down and then one of us would call Station X. I had no idea what Station X was.” Pat was one of many secret ‘listeners’, whose precious encoded data was being sent to the rapidly expanding team at Bletchley.

In late 1941, for the first time in British history, conscription for women was introduced. By then Bletchley was already reliant on a massive female workforce, like so many other wartime institutions. A group of the original cryptanalysts had sent a stern missive that October to Winston Churchill saying they did not have sufficient resources and staff, which saw the prime minister instantly and dramatically scale up operations. It would keep growing so that by 1944, Bletchley employed 8,743 workers, three-quarters of whom were women.

Although ‘posh’ civilian girls were first to arrive, the sheer numbers required saw the majority of staff being recruited by the military services. Among them was Charlotte Webb (née Vine-Stevens), who was 19 when she was selected from her Auxiliary Territorial Service training camp. Shifts took place in a small room in the Bletchley mansion.

“I worked on the card index, putting things into date order and registering them under their call signs. Nothing was in clear language. It was all in groups of letters or figures on sheets of paper – masses of them,” says Charlotte. Her job was not to understand, but to register every message passing across her desk.

3 women of Bletchley Park

Pamela Rose (née Gibson)

Still alive at the time of writing and thriving at 101, Pamela’s war work began with her recruitment to the indexing department of Hut 4. She was one of the very few examples of women being promoted from “humdrum roles”. Pamela became head of Naval Indexing, a section that has subsequently been hailed as a precursor of the Information Age. Co-ordinating vital fact-finding forays long before the advent of the microchip, she remains modest about her wartime achievements. “I think I was promoted because I couldn’t type! Yes I suppose most of the Heads of Sections meetings were with men. I was given my own room and had some responsibility but I missed the girls’ chatter.”

Pat Davies (née Owtram)

While she was not based at Bletchley, Pat was a Wren in the Y Service, which saw her move between three English coastal locations. Her final listening post was Abbot’s Cliff in Kent. At the age of 95, Pat remains a tireless champion of her secret war work: lectures, theatre tours, television appearances, she uses any means available to explain her time at the coalmface of Britain’s massive interception mission. “Doing this work at an early age meant my life went down a totally different track. Before the war, my parents said ‘we can’t afford to send you to university’, but in the end I went to three of the very top ones.” Pat studied at St Andrews, Oxford and Harvard, before she embarked on a stellar media career as a producer in the then-new medium of television.

Charlotte Webb (née Vine-Stevens)

In 2015, Charlotte received an MBE in recognition of her tireless campaigning and support of Bletchley Park Trust, the museum that has enlightened millions about the work done in secret by thousands of men and women. The award is the pinnacle of an impressive CV. As a reward for a meticulous performance at Bletchley over three years, Charlotte was transferred in 1944 to a new building in the US: the Pentagon. “I was staggered by the invitation. Me? A humble staff sergeant.” Despite teething problems, cross pollination between British and American codebreakers had increased since 1942. “I was the only ATS (Auxiliary Territorial Service) girl in the whole building! I did the same job I left behind at the Park. I suppose I was a natural administrator.”

Learn to love the Bombe

It was Turing’s development of the bombe that radically increased the rate at which Enigma could be read. By 1944, a force of 1,676 Wrens were dutifully tending more than 200 bombes – described as having the appearance of “great metal bookcases” – which were harvesting up to 18,000 Enigma messages daily. Alongside Pat’s interceptions and Charlotte’s data processing came Wren Ruth Bourne (née Henry)’s mechanical vigilance as another component on the codebreaking conveyor belt. Her job was to operate one of the bombes. Churning with around 100 rotating drums, 12 miles of wire and one million soldered connections, it made for an intimidating prospect, but what Ruth thought of her work was irrelevant. “Nice girls do what they are told,” she explains.

The bombe was just the first of the industrial sized behemoths that transformed life at the Park. Another Wren, Joanna Chorley (née Stradling), worked in the Newmanry, a section tasked with reading the highly sophisticated ‘Fish’ communications sent using the Lorenz cipher between Hitler and his high command. Up to a hundred times longer than Enigma, Fish messages were invaluable. So much so that a technological whopper was born to analyse their contents: Colossus.

Joanna remembers her first meeting with the machine, which was the size of a room: “It was ticking away, and the tapes were going around and all the valves, and I thought what an amazing machine. Like magic and science combined!” Joanna had fallen in love with the world’s first electronic computer. “It’s a bit silly really isn’t it? But I did love the beast,” she recalled.

Repetition and reward

For many of the Bletchley Girls, their roles were compartmentalised and prioritised accuracy, stamina and occasionally a foreign language. Lady Jean was disappointed with her job. Her shift work, designed to make up for a short fall of bombe machines, was frustratingly repetitive.

“I marked letters in German messages, then perforated those same marks and compared one message on top of another. If three holes were on the top of three other marked ones, these were put through the hatch to the next room. Doing this for a year sent me nearly crazy.”

Exceptional moments were keenly savoured. Rozanne Colchester (née Medhurst) was a teenager who could speak Italian courtesy of a childhood spent in Rome. Her basic decoding was formulaic and the information revealed fairly dull, but late one night “after many trials and errors I found myself faced with a message that made sense”. In her small work room in Buckinghamshire, she read something no one else in the Allied forces knew – in three and a half hours, Italy’s SM.79 torpedo bombers and SM.82 transport carriers would leave Tripoli and head across the Mediterranean. With the Desert War over by June 1943, the crippled Italians were making for Sicily, but thanks to Rozanne they never reached their destination. The information she read was radioed to the RAF in North Africa. “Very soon our aeroplanes were in the air and all the Italian aircraft were shot down!”

Few experienced such stand-out moments, but all of the women remember the onus placed on secrecy. No one could forget their introduction to the Official Secrets Act. Charlotte recalls a vast document she was forced to read on the spot. Ruth was told if she broke her oath of secrecy, she would go to prison “at the very least”. Joanna was under no illusions, either: “We knew damn well what will happen if we blab. It will kill people. We knew we couldn’t talk for a reason.”

During his only visit to the Park in 1941, Churchill described Bletchley as “the goose that laid the golden egg but never cackled”. And everyone kept their secrets for more than 30 years. Bletchley’s impact on the war is now common knowledge, but before the 1970s some Bletchley Girls weren’t even aware they had been involved in codebreaking. Pat was one of them.

“It was surprising to hear that Bletchley had achieved such great things,” she says, “because at the time we never got any feedback. We didn’t know how important we had been.”


Wartime codebreaking tales from Redcot resident who worked at Bletchley Park

Juliet Fuirer, who has just celebrated her 98th birthday, has lived at Redcot care home in Haslemere since February 2020. She recently shared memories with the care home team and the other residents about her wartime experiences working at the famous Bletchley Park in Buckinghamshire as a Morse Code Decoder.

Having been born in Lahore, Pakistan, Juliet moved to the United Kingdom when she was six. During the war, Juliet first lived in Finchley, North London but had to move out of her family home as it was bombed during an air raid.

Juliet recalls: “After we got bombed, we moved to another house in Hampstead which was also bombed! Just our luck. My father was in the Air Force, so wasn’t at home and I was sleeping downstairs. When the bomb hit, the roof came down, raining rubble and plaster on to my Mother who was sleeping upstairs. My poor Mother was trapped under the rubble and got quite a few bruises. She was so lucky that those were her only injuries.”

When she was 18, Juliet was called up and joined the Army. She was posted to Bletchley Park which was, during wartime, the world’s best kept secret and a key part of the country’s war effort against Germany. Bletchley Park was the secret base of the World War II Codebreakers and home to the UK Government Code and Cypher School (GC&CS). The teams there regularly infiltrated the secret communications of the Axis Powers (Germany, Italy and Japan). Most famously – and importantly – the team of codebreakers who included Alan Turing, cracked the German Enigma and Lorenz ciphers.

The Lorenzo was high security teleprinter cipher machine which enabled the Germans to communicate by radio in complete secrecy and the Enigma machine implemented a substitution cipher. This encrypted a message by substituting one character for another. Alan Turing and his team broke the ciphers and are credited with shortening the war by two years and saving as many as two million lives.

During her wartime Service at Bletchley Park, Juliet worked decoding morse code messages which were being transmitted from a German tank corp. Not only did Juliet have to decipher the Morse Code, she then had to translate the messages from German into English so they could be relayed to the officers.

Talking about her wartime endeavours, Juliet said: “Working at Bletchley Park was an intense job. I signed the Official Secrets Act so I wasn’t allowed to tell anyone what I was doing, what I was working on, not even how long my shifts were. Not even my friends or family knew what I was assigned to do. It really was top secret stuff.”

Juliet continued: “Home was a barrack hut which housed around 30 bunks. It was very cramped with not much space at all. In fact, the bunks were so close together I could stretch out my arms and touch my work colleague who slept next to me. There was a brasier at one end of the hut, but no heating at all at the other end. It was a real competition to get a bunk as close to the heat as possible.

“Our washrooms were in a separate building and not very nice. They had concrete basins and huge concrete baths – it was a struggle to get enough hot water to fill them.”

Her wartime living quarters and basic facilities didn’t faze Juliet, she added: “I didn’t complain. I was honoured to be doing such important work for my country. I didn’t question anything, I just got on with what I’d been asked to do.”


The Secret Lives of Codebreakers: The Men and Women Who Cracked the Enigma Code at Bletchley Park

Bletchley Park was where one of the war s most famous and crucial achievements was made the cracking of Germany s Enigma code in which its most important military communications were couched This country house in the Buckinghamshire countryside was home to Britain s most brilliant mathematical brains, like Alan Turing, and the scene of immense advances in technologBletchley Park was where one of the war s most famous and crucial achievements was made the cracking of Germany s Enigma code in which its most important military communications were couched This country house in the Buckinghamshire countryside was home to Britain s most brilliant mathematical brains, like Alan Turing, and the scene of immense advances in technology indeed, the birth of modern computing The military codes deciphe

The work at Bletchley Park was some of the most secret in the war. The British needed to break the Enigma codes, used by the Germans to transmit messages. Doing so meant that, by the end of the war, the British intelligence service were often reading messages before they reached Hitler's de

First, I need to declare an interest: my grandmother was a codebreaker at Bletchley Park during the war. (Yes, a codebreaker, not a wren or a secretary.) So I didn't read this dispassionately.This is an interesting book because of my family connections, therefore. It takes an interesting su

Now it can be toldI’m a Bletchley Park addict so prepare for some gushing. McKay’s book had a more social bent than most of the books I’ve read which were more focused on the mechanics of breaking the Enigma Code itself. McKay looks at the invention of the machines such as the bombe a

It has been some 40 years since Bletchley Park was first “outed”, and since then there was a steady stream of revelations both shocking and intriguing. But now most of what’s interesting and intriguing has already been written up, and this book doesn’t really add a lot. For one thin


Patricia Brown obituary

Patricia Brown, who has died aged 103, was one of the leading female British codebreakers during the second world war, initially with the Government Code & Cypher School at Bletchley Park and then as the head of its German diplomatic section, based in Berkeley Street in Mayfair. Known then as Pat Bartley, she not only played a key role in the breaking of the main German diplomatic code, Floradora, but her skilful leadership and management of cooperation with her US counterparts ensured a difficult system was broken far more quickly than expected.

She had been persuaded to work at Bletchley Park, Buckinghamshire, by Emily Anderson, the leading British female codebreaker during the interwar period, who was billeted on her parents at their home in Swanbourne, eight miles from the wartime codebreaking base.

In 1936 Bartley had gone to Lady Margaret Hall, Oxford, to study philosophy, politics and economics. However, two years later she suffered a nervous breakdown and was recovering at home when Anderson arrived. A former professor of German at University College Galway, Anderson was immediately impressed by her intellect and fluency in German.

When she first arrived at Bletchley Park, Bartley was put to work – with nothing more than paper, pencil and her knowledge of the language – on the main German diplomatic code, a system that had largely been ignored during the interwar period because it was deemed too difficult.

Dubbed Floradora after a popular British musical comedy, it was a code that was subsequently enciphered twice, leaving German diplomats with the mistaken belief that it was unbreakable. This bred carelessness, examples of which Bartley was swift to spot, enabling her to make progress. She was soon given more staff and, at the age of 24, made head of the section.

Breaking Floradora was an extensive process. It was a double additive code system. The message was initially encoded to produce a stream of five-figure groups, each of which represented a German word or phrase. Then two machine-generated streams of five-figure groups were lined up beneath the encoded message and added to it using non-carrying arithmetic for instance, 7 + 5 producing 2 rather than 12. The name Floradora is thought to have been chosen because it echoed the two indicator groups at the beginning of the message which together formed a palindrome.

Bletchley Park’s diplomatic and commercial sections moved to Berkeley Street in early 1941, giving Bartley more autonomy and enabling her to increase liaison with the Americans. They responded far better to her requests for collaboration than they did in many other areas and were grateful for her perspicacity in spotting German mistakes and other ways into the code, not least one technical error in the system that immediately halved the workload.

Patricia Brown’s section at Bletchley Park, Buckinghamshire

The official history of GCHQ, John Ferris’s Behind the Enigma, which lists her as one of the top four female British wartime codebreakers, also claims that her “brains, beauty and vivacity” swept senior codebreakers off their feet when she first arrived at Bletchley. A better measure is perhaps a Brown family anecdote about an American officer who had regularly received her thoughts on codebreaking problems via telex and as a result knew her purely for her exceptional codebreaking skills. On finally meeting her in person, he is said to have exclaimed: “So you’re the famous Miss Bartley. But you’re beautiful!”

By May 1942, she and her team, which included the US film star Dorothy Hyson and Ernst Fetterlein, who had been the Tsar’s personal codebreaker, were reading a small number of messages between the German embassy in Dublin and Berlin. By August, they were able to read every one.

When one of her male subordinates attempted to take credit for this, Alastair Denniston, the head of the Berkeley Street office, stepped in to make sure she received the credit, which included letters of commendation from the cabinet secretary, Sir Edward Bridges, and MI5.

Although Bletchley Park’s appointment of young women like Bartley to positions of authority epitomised a willingness to select whomever was best for the job regardless of age, sex or rank, not everyone took the same view. Breaking Floradora required the constant assistance of Bletchley Park’s Hollerith tabulating machines, which were controlled by Frederic Freeborn, whose treatment of Bartley, frequently bypassing her or holding back on her requests for machine time, was blamed by one male colleague for a second breakdown, which she suffered in 1943.

She did not return to work until after the war and then only to write two chapters of the internal GCHQ history of her section.

Born in Dhaka, then in India but now Bangladesh, Patricia was the daughter of Sir Charles Bartley, an Irish barrister who was serving as a judge, and his wife, Marjorie (nee Flowers Hamilton). He survived a number of assassination attempts but these do not seem to have affected a happy childhood for Patricia. Being sent to boarding school in England at the age of 10 was more traumatic, and she ran away from a succession of schools until finally she was home-schooled at an abbey in Brittany, where her mother and three younger siblings, two brothers and one sister, were living. Her father retired from the Indian courts in the 1930s and the family moved to Swanbourne, where he took over her education.

After the war she joined the Foreign Office, briefly sharing a flat with the actor Deborah Kerr, and met her future husband Denys Downing Brown, who had spent much of the war in a PoW camp in Germany, from which he escaped three times, winning the Military Medal as a result. They married in 1954 and, like many of the young women who had made brilliant contributions to wartime codebreaking, she spent the postwar period focusing on bringing up a family.

Her husband was posted to the Egyptian city of Ismailia on the west bank of the Suez Canal as consul general. When the Israelis invaded Egypt at the beginning of the 1956 Suez Crisis, she was heavily pregnant with their daughter, Iona. She and the couple’s young son, Andrew, were hurriedly evacuated while her husband was interned.

Further postings followed in Belgrade, Stockholm and Bonn. The family made their home in Godalming, Surrey. When her husband died in 1997, she moved to Saffron Walden, Essex.

She is survived by her children and by two grandchildren, Rosamond and Felix.

Patricia Marjorie Brown, codebreaker, born 1 May 1917 died 26 February 2021


Scholars learn about WW2 codebreakers at Bletchley Park

Chevening Scholars had the chance to visit Bletchley Park, situated in Milton Keynes, Buckinghamshire, which was used to penetrate the secret communication of the German ‘Enigma’ and ‘Lorenz’ ciphers.

Right after arriving scholars participated into activities such as workshops, guided and self-guided tours, all to learn in-depth about the park.

At the beginning of the workshop scholars heard history about Bletchley Park and learnt more about this ‘secret’ place, which shortened the World War Two by two to four years, and more importantly saved countless lives during that time. In addition, they also learned about the ‘Enigma machine’ used by the Germans during World War Two.

Bletchley Park was bought in 1938 by the head of Secret Intelligence Service (SIS) for only £6,000 using his own money. He bought it for the use of SIS and Government Code and Cypher School (GC&CS).

After that Bletchley Park became home to the brilliant English mathematician who worked for the government during the war, Alan Turing. Turing and his team broke the German Enigma code and, later on, formed the basis of modern electronic computing.

Hut 8 was the section led by Alan Turing to solve the enigma messages.

During the workshop, Chevening Scholars saw a simulation of what the codebreakers job looked like by solving some codes using an app of the Enigma machine:

Later on that day, Chevening Scholars learnt about the strategic reasons Bletchley Park had been used for. The reason to choose this place as the secret place for codebreakers was its centrality and its closeness to Oxford and Cambridge, where many codebreakers came from, in addition to the closeness to Bletchley station.

Enigma machine

Scholars also learnt about the Enigma machine that was purchased by the Germans for military use.

The possible configuration of enigma was calculated to be 3 * 10114 and the users of enigma were confident because of these large possibilities. Moreover, the cipher system of the enigma was changing daily. Nevertheless, Turing had an immersive role in breaking the code by inventing a machine known as ‘The Bombe’, which helped in reducing the work of codebreakers and, from 1941, the Enigma messages could be read. The Bombe arrived at the National Museum of Computing on 1 May 2018.

In 1942 Turing also helped in developing a technique to understand the ‘Lorenz’ cipher machine.

The mansion

The mansion which was known as Bletchley Park and BP for the codebreakers, was built by Sir Herbert Leon, and was purchased along with 58 acres for the use of Sis and GC&CC. It was home to the work of codebreakers.

The codebreakers were not allowed to tell where they were going except saying they are doing ‘a military service’. They would have been given a pass to come through the station and they were not allowed to speak about the ‘secret’ thing they were doing or they would have been killed. The work of the codebreakers was stressful to a huge extent and with great secrecy. Codebreakers were sworn to absolute secrecy, which the workers have obeyed right up to this day.

Winston Churchill, the Prime Minister during World War Two, famously described the codebreakers who worked at Bletchley Park as ‘the geese that laid the golden eggs and never cackled’.

Sadly, the codebreakers were never rewarded by anyone seeing the important work they have done.

The National Computing Museum

The work of men and women in Bletchley Park did not just help end war, but laid the foundations for the computer age.

In the museum scholars had the chance to see the world’s first modern computer in action: ‘The WITCH’.

Scholars also saw the Colossus Gallery that showed the entire World War Two codebreaking process of the ‘Lorenz-encrypted’ messages.

In addition to computers that dated from the 1950s, 60s and 70s, such as Elliotts from the 60s and IBM. These computers looked like washing machines. All of that was in addition to a collection of computers from the 1980s.

The attending scholars and I enjoyed our time in Bletchley Park and learnt a lot about this secret place.


'Vital archive'

All the workers had to sign the Official Secrets Act when they first arrived, and their stories only started to come to light in the 1970s.

An online database now lists all those believed to have worked in signals intelligence there, and at other locations.

The trust wants those on the list to add pictures and experiences, plus anybody not already mentioned to come forward.

Katherine Lynch from the trust said: "Although the habit of secrecy has remained for some veterans after it was so ingrained into them, it would now help us bring to life this unique heritage site by telling the stories of the people who achieved incredible success and shortened the war.

"The more we know about not only what [veterans] did but who they were and how they lived, the richer this vital archive will become."

Ms Lynch says the archive allows veterans to find out how they fitted in with the rest of Bletchley's work, as they were only kept informed about their own input.

"Many are fascinated to learn what else was going on," she said.

"We have had Bombe operators who only heard about the Enigma machine when its story was revealed in the 1970s."


Watch the video: WW2 Codebreakers: Bletchley Park activities revealed in unique footage - The Hidden Film