Kay volunteered for the Auxiliary Territorial Service as a teenager in 1940. Toward the end of her training three ATS women were killed in Chatham and she volunteered as one of the replacements. This assignment was in the Y service, which was a worldwide network of intelligence gathering.

Her work involved receiving messages from around the world, transcribing them so that they could be evaluated and passed on to various units. Some went to the Ultra decoding group at Bletchley Park. After several different locations her unit was sent to disguised purpose-built offices near Loughborough. Here she spent the next five years until the end of the war, which they knew was imminent when they received an uncoded message from Germany ‘Der Fuhrer ist kaput’! When the war ended she held the rank of sergeant.

She was sworn to secrecy and did not talk about her work for thirty years, which irritated her mother. During her time in the Y service, she worked with Special Operations Executive and intelligence officers, including Kim Philby. She thinks that her work during the was worthwhile and has been told that it may have shortened the war by up to two years.

In 1945 she married a man she met working at the same establishment, and they were both demobbed that year. She became a borough councillor and was thinking of standing as an MP but instead went with her husband to Ceylon (Sri Lanka) where they lived and worked for fifteen years.