Women Codebreakers

The Bletchley Park codebreaking operation during World War 2 was made up of nearly 10,000 people (about 75% of this number was women). However, there are very few women of that are formally recognised as cryptanalysts working at the same level as their male peers. Published books refer to the women codebreakers as:

  • Mavis Batey (formerly Lever)
  • Margaret Rock
  • Joan Murray (formerly Clarke)
  • Ruth Briggs

I have been writing a short book to introduce Mavis, Margaret and Joan (2017 UPDATE – actually, it’s grown into a 3 part series which will be available in 2017) and pay tribute to their remarkable contribution during World War 2. I will be consolidating the information found in the resources below as well as adding plenty of extras to give readers a chance to get to know more about these inspirational women.

women codebreakers, www.bletchleyparkresearch.co.uk



Click here to keep up to date on the Women Codebreaker ebook news. 

You can check out some of the  resources collated from around the web about each person.


Mavis Batey (formerly Lever)

Keith & Mavis Batey

Keith & Mavis Batey

Mavis Lilian Lever was born on 5 May 1921 in London. After a convent education she attended University College London studying German Literature.

She was recruited from University College London into intelligence by her professor Leonard Willoughby, a former Room 40 colleague of Dilly Knox.

Her studies had given her good language skills that landed Mavis working for the Foreign Office’s Ministry of Economic Warfare (MEW) blacklisting companies in neutral countries working with or supplying material to the Germans.

Her logical thinking got her noticed and in June 1940 found herself at Bletchley Park meeting eccentric codebreaker, Dilly Knox for the first time.

Mavis Batey’s has written an insightful biography of Dilly Knox called Dilly: The Man Who Broke Enigmas. It is a good introduction to the Government Code & Cypher School codebreaking operation at Bletchley Park as well as a personal account of her codebreaking successes and contribution to the Battle of Cape Matapan, which put the Italian Navy out of World War 2.

http://en.wikipedia.org/wiki/Mavis_Batey – Mavis Batey’s profile on Wikipedia

Canary Islands Service Enigma Break – her account of how her colleague Margaret Rock broke a new Abwehr Enigma cipher in May 1943

An audio interview with Mavis Batey by author Michael Smith hosted on Audioboo

Margaret Rock

Bletchley Park Margaret RockDear Codebreaker was published very little was known about Margaret Rock, another woman codebreaker at Bletchley Park.

Margaret Alice Rock was born on 7 July 1903 to Dr Frank Ernest Rock and Alice Maud Simmonds. She was educated at the North Middlesex School and graduated from Portsmouth High School (part of the Girls’ Day School Trust) in 1919.

She arrived at Bletchley Park on 15 April 1940. At thirty-six she was older than most of the young girls at Bletchley Park who were recruited straight from school or university. As a graduate mathematician from Bedford College (now part of Royal Holloway) and statistician, Margaret made an ideal recruit for Dilly Knox’s Research Section in Cottage No.3.

Between October and December 1941 Dilly and his all-female team in the Cottage broke the Abwehr (German Military Intelligence) Enigma machine. This significant break allowed Britain to control the German spy network in Britain and feed misinformation back to Hitler about where Britain would attack on D-Day. Dilly gave Margaret and Mavis all the credit for the Abwehr break.

You can read how the Abwehr Enigma machine was broken here (link to a document on www.bletchleypark.org)


Margaret Rock 1950s

During her time at Bletchley Park, she found her true calling as a codebreaker and continued to work at Bletchley Park then GCHQ for the next 20 years.

The book Dear Code Breaker: The Letters of Margaret Rock (Bletchley Park Code Breaker & John Rock (Parachute & Glider Forces Pioneer) (BookTower Publishing 2013) is a touching and unique insight into the daily life of Margaret Rock through a series of letters written by Margaret and her brother John Frank Rock. It offers a fascinating insight into the love and loss of this close family unit and spans significant world events such as World War 1, the Fall of France and their pioneering careers during World War 2.

You can find out more about Dear Codebreaker and watch a video of how I discovered Margaret’s personal papers at www.dearcodebreaker.com. The website is a growing digital archive of Margaret’s papers.

Click here to read more about Dear Codebreaker and get the links to buy your copy today.

You can find references to Margaret and the other women codebreakers in the following books:

The Secrets of Station X: How the Bletchley Park codebreakers helped win the war by Michael Smith (Pan Books, 2004).

The Secret Life of Bletchley Park: The WWII Codebreaking Centre and the Men and Women Who Worked There by Sinclair McKay (Aurum Press 2011)

Joan Murray (formerly Clarke)


Joan Clarke (Murray) 1936

Joan Elisabeth Lowther Clarke Murray was born on the 24 June 1917 in London. In 1936, after completing her education in Dulwich High School she studied mathematics at Newnham College, Cambridge. By 1939 she had completed Part I and II of her Mathematics Tripos, and completed Part III (Honours) in 1940.

Her Geometry supervisor, and Bletchley Park codebreaker, Gordon Welchman recruited her to the Government Code & Cipher School in June 1940. After a period of clerical work, Joan’s abilities soon led her to becoming one of the few women codebreakers at Bletchley Park.

I love the story that a pay rise was engineered to recognise Joan’s abilities and contributions to the team. She was promoted to Linguist even though she spoke no other language. Joan  ‘enjoyed answering a questionnaire with ‘Grade: Linguist, Languages: none’.

Records describe Clarke as ‘congenial but shy, gentle and kind, non-aggressive and always subordinate to the men in her life‘ yet she was well-respected by her male peers and became Deputy Head of Hut 8 in early 1944. This was indeed rare, for there are only one or two occasions were women held leadership roles at Bletchley Park.

Joan continued her career in codebreaking after the war at GCHQ and received and MBE in January 1946 for her contributions during World War 2.


Joan Clarke with Bletchley Park colleagues March 1946

The above information has been summarised from a brilliant article written by  Lynsey Ann Lord: extracted from a University of St Andrews honours project. You can read the full Joan Clarke Biography article here.

See enigmatic Joan talk about Alan Turing in the video extract ‘My Engagement to Alan Turing by Joan Clarke (later Murray).

Chapter 14 – Hut 8 and Naval Enigma Part 1 (written by Joan Murray) found in Codebreakers: The Inside Story of Bletchley Park by F.H. Hinsley & Alan Stripp (Oxford University Press, Oxford, 1993).

The Alan Turing: Enigma by Andrew Hodges (Simon & Schuster, London, 1983)

The Secrets of Station X: How the Bletchley Park codebreakers helped win the war by Michael Smith (Pan Books, 2004).

From the Archives: A Lady Codebreaker Speaks: Joan Murray, the Bombes and the Perils of Writing Crypto-History From Participants Accounts by Colin Burke and includes an article by Joan Murray.

Joan Elisabeth Lowther Clarke Murray article by J.A.N Lee, IEEE Annals of the History of Computing 23 (1) (January-March, 2001), 67-72.#

The Official History of Hut 8 1939 – 1945 by A.P. Mahon

Audrey Ruth Briggs

I am only just starting the research into Audrey Ruth Briggs (known as Ruth at Bletchley Park), who was a German scholar from Newnham College, Cambridge. In the meantime, you can find a short biography of Ruth here and information about her husband Oliver Churchill here.


Thank you to the Churchill family, see  www.tobychurchill.info here for permission to reproduce the photographs.

Chapter 24 of Codebreakers: The Inside Story of Bletchley Park (article by Christopher Morris about the German Navy’s 24 hand ciphers refers to Ruth Briggs as a talented codebreaker) by F.H. Hinsley & Alan Stripp (Oxford University Press, Oxford, 1993).

Please note: I reserve the right to delete comments that are offensive or off-topic.

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  1. i work in a nursing home in brighton and today had the great pleasure of photographing a lovely lady called ruth real name alma her bletchley medal and letter from david cameron she is such a charming lady but unfortunately suffers from dementia but always remembers her working days .