Mavis Lever was studying German at University College London when war broke out. She decided that her thesis on the German romantics would have to wait, and promptly offered her services to the Foreign Office as a spy.
She had little idea of what spies did, she now admits. She thought it had something to do with "seducing Prussian officers". Instead, she found herself ensconced in what had been a labourer's cottage in Bletchley Park, breaking codes and changing the course of the Second World War.
At one point, she was given an intercepted message from the Italian high command to decode. She worked out that it said: "Today's the day minus three." With the code broken, Dilly Knox's team was able to deduce the complete battle order of an Italian fleet that was moving in to attack a British convoy in the eastern Mediterranean. To guard Bletchley's secret, a reconnaissance plane was sent out before the battle to "spot" the oncoming fleet. The Italian fleet was destroyed at the Battle of Matapan, after which the Italian navy stayed out of the eastern Mediterranean for the duration of the war.
But, like everyone else at Bletchley, she received no public recognition until the late 1970s. Neither did her husband, Keith Batey, who was recruited to Bletchley as soon as he had graduated from Cambridge. When Mrs Batey gave a talk recently at her granddaughter's school, one of the girls remarked in amazement: "You kept quiet for 30 years? I couldn't have kept quiet for 30 minutes."
But she says: "Actually, I was lucky, because I married a mathematician from Hut 6, so although we never talked to the family or anyone else, we have talked about it to each other.
"Other people had to force it so far down that they have forgotten it all and it's very difficult to collect oral history. It was the way to do it. Nobody talked to anybody outside their own unit, because if the Germans had ever found out that we had broken their codes, that would have been the crown jewels gone."
The years of collective silence, she fears, means that the contribution of a few well known figures, such as Alan Turing, is over-emphasised at the expense of all the others.
To her, Turing was an aloof eccentric, very difficult to talk to. When he joined the team in cottage No 2, he shut himself away in the loft to concentrate on breaking the German naval code.
She said: "One should never forget the Poles who first uncovered Enigma. And Dilly Knox arrived absolutely on day one. He was the pioneer. He was an absolutely wonderful character and very easy to work with, but he was odd, just like someone out of Alice in Wonderland."
Mrs Batey, who is now 87, also plays down her own extraordinary contribution towards taking the Italian navy out of the war.
"I must absolutely emphasise that I take absolutely no credit for this. I was the one who happened to get the message to decode" she said.
"Most of the time, we never knew what it was that we broke because once we had worked out the crib, we passed it to a machinist to decode the whole message. Matapan was one of the very few occasions when we knew what happened next.
"When my local paper came to interview me, I told that I don't want to see a headline saying 'Bognor Regis Woman Won the War'."