My mother-in-law Ann Cunningham (nee Lavell), who has died aged 90, was one of the last survivors from the early days of Bletchley Park. She arrived at the wartime codebreaking centre in 1940, as a 17-year-old WAAF – having added a year to her age in order to join up. Initially she worked as a typist, suffering the indignity of early morning physical jerks to the strains of Teddy Bears' Picnic, and struggling to satisfy a healthy appetite on wartime rations.
She kept up her morale, and that of colleagues, by writing comic verse, with her friend Julie Lydekker, in a collection classified for years as top secret. It had to be passed from hand to hand inside the organisation; it was eventually rediscovered, decades later, in the Public Records Office at Kew. Food was a constant theme: one piece began, "Now what is this upon my plate/Of microscopic size?"
Subsequently she became PA to Josh Cooper (head of the German Air Section), whose legendary eccentricity had, she maintained, been exaggerated: for instance, the incident when he threw his empty teacup into the lake because he could not think what else to do with it was an isolated event, not a habit.
After the war Ann left Bletchley Park, but returned soon afterwards to what became GCHQ. She worked as PA to Hugh Alexander, head of cryptanalysis: she remembered him taking time off to give character evidence at Alan Turing's notorious trial for indecency in 1952. Later in the decade she was posted to Washington, along with Peter Marychurch, the eventual director of GCHQ in the 1980s. She became close to a colleague, Charles Cunningham, who had been a cryptanalyst at Bletchley Park during the war. After a leisurely courtship they married in 1962.
Late motherhood suited Ann: she was delighted to overhear her teenage daughter describe her parental style as "unorthodox, but on the whole convincing". But life also brought tragedy, with the death of her son Giles in 1989, aged 23.
In old age she was described as one of the "beloved venerables" of an extended clan of cousins. She was fearless and undaunted to the end: in her last year she swam in the sea, took singing lessons, and tried her hand at riding for the first time since the war.
Charles died in 2006. She is survived by her daughter, Naomi, and sister, Cherry.
