Special: The Debs of Bletchley Park

Main House 2 - small
The mansion at Bletchley Park, the nerve centre of the British code-breaking efforts in WWII.


Reporter: Emma Crous.

The world today may be obsessed with mobile phones, the Internet and all kinds of advanced technology, but the ease of communications we take for granted owes a huge debt to the incredible efforts of staff who worked at Bletchley Park in the UK during the Second World War.

Bletchley Park played a monumental role in Britain’s war effort, helping the Allies decipher the complex codes and ciphers the German military used to communicate in secret (or so they thought), and is believed to have helped shorten the war by several years, saving millions of lives.

In January, a special event was held at Bletchley for the launch of a new book “The Debs of Bletchley Park” (in reference to the female debutantes) by Michael Smith, Bletchley’s chief historical adviser.  The book focusses on the stories and memories of the women who lived and worked at Britain’s most important intelligence facility during WWII.

We sent our reporter, Emma Crous, to Bletchley for the day, which turned out to be a fascinating insight into the paradox of the story of Bletchley Park – the communication hub of the nation shrouded in absolute secrecy for years.


Bletchley Park - Main House
The mansion at Bletchley Park today. Click to enlarge.

Bletchley Park in Buckinghamshire was bought by the UK government in 1938, in order to house the HQ of the Government Code & Cypher School (GCCS) which in time became the organisation known today as GCHQ. Before being chosen as HQ, it was visited in May 1938 by Admiral Sir Hugh Sinclair, head of the Secret Intelligence Service (SIS or MI6) under the cover of “Captain Ridley’s shooting party”.

Part of the reason he chose Bletchley was because of its relative safety and distance from London and its rail links to the rest of the country, but it was also close enough to the university cities of Cambridge and Oxford where many of the experts were recruited from.

At the height of WWII, 12,000 people worked at Bletchley and its related stations, and approximately 8,000 of them were women, whose roles included everything from code breaking to filing. All of them played an essential part in the effort which saved countless lives by predicting where the German bombers would attack, helping sink the U-Boats that were torpedoing supplies from the U.S. and by playing a key role in allied successes in North Africa and Europe.

Bletchley Park is largely considered the birthplace of the digital electronic computer.  But the communications technologies and data processing techniques pioneered at Bletchley were also the forerunners to today’s information age, as new machines were developed by the country’s sharpest minds in order to help speed up the code breaking effort and bring the war to its conclusion.

The world’s first search engine

The Bombe machine
Replica of the Bombe machine.

Arriving at Bletchley today, the visitor centre is located in what used to be called “Block C”, a brick-built soundproofed building.  This was the machine room where the names of people, places, cover names, military unit radio stations and countless other significant details were recorded onto punched cards using “Hollerith machines”.  It was effectively the data centre of the intelligence unit and formed a huge cross-referencing system stored in card index files. Different machines, ranging from the size of a typewriter to a piano, were used to punch, sort and collate the cards, and the machines were constantly adapted under conditions of absolute secrecy. At its peak, 2 million Hollerith cards were produced each week. Google (who has contributed large sums of money towards the restoration of Bletchley) have dubbed Block C “the world’s first search search engine”.


Enigma Machine 2 - small
An Enigma machine at Bletchley Park.

Bletchley Park operated round the clock, using an 8-hour shift system which ensured that it was always in constant operation. Basically, a production line of cryptography, traffic analysis, data storage and direction tracking – all of which were kept isolated and compartmentalised so that staff in one particular section had little exposure or idea of the significance of the work they were doing in relation to the bigger picture. The intense security surrounding the activities at Bletchley meant that few of the staff really knew what anyone else was doing , despite working almost shoulder to shoulder for years on end.


The book launch for The Debs of Bletchley Park was held in the dining room of the mansion itself, which dates back to the 1870’s  and was originally being the family home of Sir Herbert Leon, a wealthy stockbroker. During the war, the mansion (or ‘the main house’ as it was known), was used as the HQ & recreational building, housing the offices of senior members of staff.  The country’s first telephone exchange was in the billiard room, and the major code breaking sections initially worked on the ground floor before expanding into a series of huts built in the grounds of the park, where vast amounts of intelligence was decoded every day.

Inside Hut 6 Pic - small
Inside Hut 6.

One of the outbuildings know as Hut 6, was built in January 1940 for the decryption of Enigma messages intercepted from the Germany Army and Air Force. The standard three-rotor Enigma machine was adapted from an earlier commercial version which was developed as a banking machine, and was capable of producing 159,000,000,000,000,000,000 or (159 x 10^18) possible combinations (further more sophisticated versions with four and five rotors were developed during the war).

Each one of the machine’s billions of possible combinations scrambled messages into different cypher text, which the Germans believed to be impenetrable. However, made easier by weaknesses in the way the machines were used and mistakes made by the German operators, the British were able to decipher the scrambled messages. At midnight each day, the Enigma settings were reset and so the British codebreakers faced the daily challenge of deciphering the new settings (known as the ‘Daily Key’).

Inside Hut Pic 2 - small
Set from the exhibition of the film: The Immitation Game

Initially, perforated sheets, known as Netz by the Codebreakers, were used to help deduce part of each Enigma Key. Later, efforts were assisted by the Bombe machine, the cryptanalytical machine designed by Alan Turing. The Bombe was used to discover the daily settings of the Enigma machines on the various German military networks: specifically, the set of rotors in use and their positions in the machine, the rotor core start positions for the message—the message key—and one of the wirings of the plugboard.

Once the codes had been partially deciphered, they would be passed onto the sister hut (huts worked in pairs), where the messages would be translated and analysed by a different team. (Secure data transfer between the huts took place via a specially-built chute between the buildings, and a broom handle was used to push a wire basket containing the information through the chute!)

Messages were classified either as Secret, Top Secret or Top Secret U (“Ultra”). The Ultra category was designated for intelligence on the enemy’s movements and plans, and only a handful of top commanders were privileged enough to receive it, but were also forbidden to act upon it until the Germans had been deceived into thinking it came from another source. Apparently, some of the intelligence could not be acted upon, as doing so would alert the enemy that their communications had been deciphered.

The veterans of Bletchley Park

Debs of Bletchley Park book launch
The veterans who attend the event at Bletchley.

The veterans pictured in the photo above (from left to right) are Lady Marion Body, Jean Pitt-Lewis, Betty Webb, Marigold Freeman-Attwood, Margaret Mortimer, and Jean Tocher.

An emotional and physical toll

Of the more than 8,000 staff at Bletchley during the war, 75% of them were women, some of whom were members of the Women’s Royal Naval Service (WRNS), affectionately known as ‘Wrens’.  Six of the Veterans who feature in the new book took part in a question and answer session, which brought to light just how incredibly hard work it was at Bletchley. The women would work for a solid eight hours day in, day out, and on occasion would have to work double shifts. The work was challenging too, as many of the women would have to concentrate intensely all day listening and scribbling down letters and codes – one mistake and it could have a huge impact on the intelligence gathering.

So hard was the work, that it took a huge emotional and physical toll. Marigold Freeman-Attwood, who worked on Colossus said that she suffered from hair loss from the constant fatigue and stress of the job. But that didn’t stop Bletchley’s human data processing operation from stopping – it was in constant operation, as even the machines needed operating by human hand, as well as people to interpret the data they deciphered and collated; the women working ceaselessly like machines themselves – sifting through letter after letter to identify even the tiniest of clues.

The geese that laid the golden egg

Churchill referred to the women of Bletchley as “the geese who laid the golden egg but never cackled” in reference to the impact they had and the fact that they never discussed their work, even amongst each other, for decades afterwards. It’s ironic that even though the focus of all their work at Bletchley was related to intercepting communications, everything they did was shrouded in absolute secrecy, and outside communication was strictly forbidden.

Winston Churchill
Churchill called Bletchley staff ‘the geese that laid the golden egg but never cackled’.

It’s testament to their dedication that the women of Bletchley didn’t reveal what went on even to their parents, husbands or children.

“Whenever you left your room, you always shut your door firmly,” Lady Marion Body explained, who never even told her husband what she did during the war.  Even when he urged her to reveal her decades-long secrets to tell him, she simply answered with a resolute “No’. Lady Marion Body, from Stanford Dingley in Berkshire, was a Foreign Office civilian working on Japanese encoded messages alongside HRH The Duchess of Cambridge’s grandmother and great-aunt.

Betty Webb (who was a member of the Auxiliary Territorial Service (ATS) and worked on German police messages in the Mansion at Bletchley Park) revealed that “even when the veil of secrecy was lifted in 1975, it was many years after that, I felt free to speak”, and that it wasn’t until the end of the war that veterans were able to meet and exchange stories and learn about each other’s contributions during the war.


The Morning Room
The “Morning Room” at Bletchley Mansion, as it may have looked during the war.

Jean Tocher worked on the “allied plot” at Bletchely – a chart of the world covering four walls of a room on which the movement of the allied ships and their German, Italian and Japanese opposite numbers were plotted. But, she explained, it was the first time she had met any of the other ladies on the panel, and that finally after all these years, they were able to share stories and learn a little about the work each other had been doing during the war.

A huge contrast to today’s information age

Emma spoke in person with Margaret Mortimer (who worked in the Newmanry Registration Room receiving German messages from the intercept site at Knockholt) and Marigold Freeman-Attwood (a member of the Women’s Royal Naval Service who worked on Colossus), to learn a little more about how they feel the world has changed, and the impact modern technology and communications has had over the past decades.

Margaret Mortimer
Margaret Mortimer

Both ladies revealed that they don’t own or use a computer, although they both use basic mobile phones just to make and receive calls. When asked about the world today in terms of the advance of technology, the internet and smart phones, Margaret felt there are “no boundaries to anything” and feels a bit overwhelmed by the proliferation of so much technology, which somehow makes the world feel too big.

Marigold on the other hand thinks the modern world is great, but admits that it doesn’t feel very much like her world anymore. She was thrilled to receive dozens of likes on her daughter’s Facebook page, however, regarding the book launch.

Both ladies agreed that when they left Bletchley, the very best thing was the wonderful long-lasting friendships they established.  Many of them have met, every year since the war  in London for a reunion – but the work they did was never mentioned – their secret kept for decades.

Sometimes overshadowed by the more well known figures at Bletchley, it is only in recent years that the historical significance of the women’s contribution to the war effort has been widely recognised.

Mobile Industry Review would like to thank everyone at Bletchley Park,  Michael Smith, and especially the remarkable ladies who made the event possible. 

You can find out more about Bletchley Park here.

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