Women Codebreakers; the hidden female heroes of code cracking

Without doubt, if you ask someone to name some WW2 codebreakers, all the names they are likely to come up with will be those of men. Alan Turing, Gordon Welchman, Alistair Denniston, Dillwyn Knox, John Tiltman, Hugh Alexander, Stuart Milner-Barry, and Bill Tutte are names which might figure in a brief list of leading British codebreakers. In the USA, the list might include William Friedman, Joe Desch, Elvin Urquhart, and Frank Rowlett.

This could suggest that codebreaking is an exclusively male field, one to which women were unfitted to contribute. But nothing could be further from the truth; the reason women rarely participated at the higher levels of codebreaking was largely the result of male prejudice, not of female inability.

Even well before WW2, a several talented and determined women showed great codebreaking skills. Elizebeth Friedman (1892-1980, wife of William), started work as a codebreaker for the US War Department in 1919 and later worked for the US Navy, scoring notable successes against smugglers attempting to bring alcohol and other contraband into the USA in the prohibition years.

Elizebeth Friedman – US codebreaker

In the UK, Emily Anderson (1891-1962) was a ‘Hushwaac’ in WW1 – one of twelve women from the WAAC who were recruited as codebreakers in 1917 – and she stayed on after the war in GCCS as its sole female codebreaker. She has been described by John Ferris as ‘among the best cryptanalysts in the world’.

At Bletchley Park, there were eventually some 9,000 people employed, contributing to the work of this mighty production line of intelligence; intelligence derived from breaking enciphered enemy radio messages.

Women outnumbered men at Bletchley Park by about 3 to 1

In one sense all were ‘codebreakers’; they were, after all, employed in an institution dedicated to breaking enemy codes (and ciphers). However, the vast majority weren’t actually wrestling mentally with the problems of working out what GPCFF WNBFT IYRAM BBXFE TEQCB OHJJR could possibly mean.

The pyramid was a very flat one, with few at the top, challenged daily to interpret apparently meaningless strings of letters. Below them, in the broad lower reaches, were hundreds involved in the essential work of sorting, transcribing, indexing, translating and typing. The majority of these ancillary staff were women – by 1945, women at Bletchley outnumbered their male colleagues by three to one. One of them, Betty Webb, was doing such valuable work that she was transferred to the Pentagon between VE Day and the surrender of Japan in August 1945.

Although the women were, by and large, officially recruited for these more lowly roles, perceptive senior men deliberately sought out or recruited talented women who had codebreaking potential.

Renowned among these was Dilwyn (‘Dilly’) Knox, who studied the interview notes made by the Foreign Office interviewer, and then drafted some of the brightest women into his team. All of his immediate team were women, giving rise to the nickname ‘Dilly’s Fillies’, supposedly picked for their good looks, but it was actually their brains which caught Dilly’s attention.

Amongst these hand-picked girls were Mavis Lever, Margaret Rock, Claire Harding, and Phyllida Cross, and their success against Italian Naval Enigma gave Admiral Cunningham the opportunity to surprise the Italian Mediterranean Fleet at Matapan, and inflict such damage that it was never a serious threat again. Admiral Godfrey, Director of Naval Intelligence, credited Knox’s team with this victory, and Cunningham himself made a point of visiting Bletchley to thank the team in person.

So, there were women codebreakers at Bletchley – but they faced an administrative hurdle: Civil Service rules defined certain jobs as male-only, making it impossible for a talented woman to be officially classified (and paid) as a codebreaker.

Obtaining appropriate promotion and pay for codebreaking women meant that, initially at least, they had to be given some other job description. Joan Clarke, for example, was recruited into codebreaking by Gordon Welchman because of her proven mathematical ability, but had to apply to be a ‘linguist’, despite admitting on her application form that she had no linguistic skills.

Joan Clarke, talented mathematician and codebreaker, could
only be officially classified as a ‘linguist’

In the USA, no such subterfuge was required. Even before Pearl Harbour, the US Navy started to recruit women from prestigious colleges to be trained as cryptanalysts. The US Army followed suit, and by the end of the war, about 11,000 women were codebreakers, outnumbering their male colleagues.

In the UK, therefore, male prejudice worked in two ways: firstly, senior (male) staff were frequently of the opinion that women weren’t good enough for codebreaking work, and secondly, even if a woman was deliberately recruited (by a more perceptive man) as a codebreaker, she could not be officially classified as one.

The inevitable result is that anyone now scanning contemporary staff registers, pay lists, etc, will underestimate the number of women codebreakers, because their skills and roles have been buried under inappropriate job descriptions.

We will never know how many of the six or seven thousand women at Bletchley were actually codebreakers, despite being listed as typists, filing clerks, indexers or secretaries. We can, however, be sure that many of them were codebreakers, and their skills and dedication contributed to Allied victory.

‘National Geographic’ pays tribute to Betty Webb,
who worked on Japanese messages at Bletchley Park, and later in the Pentagon

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