This is the fifth article in a series about amazing women in tech history.
The first featured Margaret Hamilton, the software engineer who helped land us on the moon. The second featured Grace Hopper, a programming pioneer and first woman to be a US Navy Admiral. The third featured the ENIAC programmers, who were pioneers ignored by history. The fourth featured Katherine Johnson, the mathematician who guided men to the moon.
War is a time of secrecy. Some small secrets are taken with soldiers to their graves, while bigger ones are hidden away forever by the military mights involved. Once in a while, historians uncover truths that might never have been revealed. Sometimes there are government secrets that become declassified decades after the fact.
In 1974, F. W. Winterbotham published a book called The Ultra Secret. He revealed British details that were classified as “ultra secret”, which was the British government’s highest level of secrecy even above “most secret”. The public came to know that 30 years earlier there had been an incredible codebreaking effort at a site in Buckinghamshire called Bletchley Park.
The work carried out at the Park has since been estimated to have shortened the war by 2-4 years and saved millions of lives. There are countless soldiers, pilots, and sailors who we know were certainly saved by the codebreaking performed in the middle of England during World War II. At the height of the codebreaking activities, there were around 10,000 people working at Bletchley Park. What has only become evident in more recent years is that the majority of the workers were women sworn to secrecy.
Signals intelligence was taken very seriously by the British government since World War I since armed forces around the world were using encryption devices to hide the meaning of their communications. The ability to decode these signals was of the utmost importance so the British government created the Government Code and Cipher School (GC&CS), which some people referred to as the Golf, Cheese, and Chess Society. Here staff were trained to decipher secret communications that might someday turn the tide of war.
In 1938 Sir Hugh Sinclair, head of the Secret Intelligence Service (MI6), bought a mansion and surrounding grounds at Bletchley Park in Milton Keyes. It was to become Britain’s codebreaking headquarters during World War II. Since this information went public, many of us have heard about important people like Alan Turning (especially since the recent Benedict Cumberbatch film). What’s less well known is that there were 12,000 different people involved at Bletchley Park and most of them were young women between the ages of 18 and 24.
Modern computers were sci-fi fantasy during World War II but the devices developed for codebreaking at Bletchley Park led the way to the computers we’re used to today. The Germans were using a device called Enigma, which let them encrypt their communications. If you knew how the device worked and you knew the starting settings, you could decode a message. However, there were millions of potential starting positions so it was extremely difficult to decode by hand though many did just that for years.
Back in 1932, the Polish Cipher Bureau revealed that they had broken the first German Enigma messages. Their cryptologists reverse-engineered the Enigma machine and these advancements eventually led to the “bombe”, an early computer that could figure out potential starting settings for Enigma messages much faster than any human could. Alan Turing is one of the people famous for the great work developing the bombe.
Sadly, the bombe didn’t work by itself. You couldn’t just click a button and let it do its thing. It was a very hands-on device that most people would barely recognise as a computer. People needed to be brought in to operate the machine. Even then, the bombe didn’t decode the messages itself. It identified wheel orders that were possible, reducing the potential work for the codebreakers further down the line. So Bletchley Park needed cryptologists, bombe operators, codebreakers, translators, cooks, cleaners, drivers… and they all had to work in absolute secrecy.
To operate the bombe, the government enlisted women from the Women’s Royal Naval Service (WRNS or “wrens”). Officially they were listed as serving on a ship called the HMS Pembroke V when in reality they were codebreaking 100 miles from the sea. As the bombe proved to be successful, more codebreakers were needed to work on the messages and more people were needed to do all the other tasks down the line. Thousands of workers were needed so women were brought in from all over Britain.
Women were often brought into the project after being approached at university or because of trusted family connections. The leaders of Bletchley Park looked for women who were linguists, mathematicians, chess champions, and even crossword experts. In 1942 the Daily Telegraph hosted a competition where a crossword was to be solved within 12 minutes. Winners were approached by the military and some were recruited to work at Bletchley Park.
New recruits at the park were given a lecture on the importance of secrecy and made to sign the Official Secrets Act 1939, which is why we never knew about these people at the time. All staff signed and were told not to talk to each other about their work at meals, when travelling, or even in their own huts. The work was ultra secret and some women have refused to discuss their work even to this day.
Jean Valentine had never left Scotland before when she was told to come to London for training before starting work as a bombe operator. This excellent video explains the type of work she did with the other women in Hut 11 of Bletchley Park:
In the past we only celebrated the likes of Alan Turing and neglected the bombe operators who were women. What we shouldn’t do today is celebrate the operators and forget that the entire Park was run by mostly young women who worked at every level.
Women helped intercept enemy messages; they brought the messages to the codebreakers; they broke the codes; they used the bombe and Colossus machines; and women did the admin, cooking and cleaning etc. The women of the WRNS Y-Service listened for communications between German ships, straining to hear the letters in code. Many of the women were trained to use guns, especially the drivers as future invasion was always a possibility. When Colossus (the first digital, electronic, programmable computer) was introduced, some of the women working on the bombe moved across to the new technology and were among the first computer programmers.
It was tough work for everyone involved. Shifts were 4pm until midnight, midnight until 8am, and 8am until 4pm for 6 days per week. There were occasional 16-hour shifts too. Some women collapsed and the strange work hours took their toll. Women did every job from cryptology to cleaning and couldn’t tell anyone about it.
The stories from the women codebreakers at Bletchley Park reveal the countless times their efforts had direct influences on the war. Althea Rayner was one of many women at the end of the codebreaking process that put the decoded messages into order and made sense of them. Sometimes they would get what they called “quatsch”, which was idle chit chat by the German operator. One night she was passed some quatsch that others have mostly ignored since it was just a long stream of useless chit chat but she had a closer look and found a message in the middle from a German sub going after a convoy. She ran to an officer and raised the alarm.
“The next day, the officer came in and told me they had managed to alert the convoy, who immediately changed course with complete wireless silence and was over 100 miles from the place where they would have been by the time the submarine reached it.
We realised from the German messages that they were puzzled but were circling. This enabled the convoy, slow as it was, to put about 200 miles on and escape altogether.”
The women of Bletchley Park were instrumental throughout the entire war. They even plotted the ships during the Normandy D Day landings. They were unsung heroes and Winston Churchill described them as “the geese that laid the golden eggs and never cackled.” Some of these women worked with one of the earliest and most powerful computers used to decode the Enigma messages and some women had roles usually reserved for men such as the Margaret Rock, Mavis Lever, and Ruth Briggs who were cryptologists. But the codebreaking at Bletchley Park required everyone to work together and they should all be remembered.
Imagine playing a major intelligence role in the war and not being able to tell anyone about it, even years after the fact. To do so much for the cause and not be able to tell your family about it. Worse still was that many of the women had no idea just how important their work had been. Because it took so many people working many different roles, yet nobody could speak about it with each other, most people had a narrow experience of the overall project. When the war was over, they took everything apart and moved on.
“I believe that Bletchley Park no longer being a secret came about some 30 years after the war and I was amazed, it was fascinating.
It seemed quite extraordinary that at last, after so many years of not being able to say exactly what you did, so suddenly to have this openness and to know really what you were doing.
It was the first time that one was aware of the importance of exactly what one did. It was wonderful – I remember being able to at last tell my family what I did.” – Barbara Peart
The story of the women codebreakers at Bletchley Park is reminiscent of the ENIAC programmers in the US. They worked on early technology that would lead to modern computing, it was a time when “the computer wore a skirt”, and they were largely written out of history for most of their lives. Today we can appreciate the impact they had and be thankful for their hard work, their sacrifices, and the lives they saved.
Bletchley Park is open as an attraction where you can learn more about Alan Turning, the bombe, Enigma, and now the thousands of women that made the project what it was.
This is the fifth article in a series about amazing women in tech history. The first featured Margaret Hamilton, the programming pioneer who helped land us on the moon. The second featured Grace Hopper, the programming pioneer who became the first woman to be a US Navy Admiral. The third featured the ENIAC programmers who were pioneers ignored by history. The fourth featured Katherine Johnson, the mathematician who guided men to the moon.
Main image © Geoff Robinson, via the BBC