My mother, Iris Warne, who has died aged 94, was one of the members of Y section at Shenley, Hertfordshire - they were the people who provided raw material during the second world war for the Government Code and Cypher School at Bletchley Park, Buckinghamshire, to decode.

The Axis Morse code messages were transcribed at a rate of 26 words per minute. In a wooden hut with a single coal stove to heat it, the team worked long shifts, covering every hour of the day and night. When finished they would go to another hut, where more than 20 young women would sleep. The comradeship that grew there outlasted the war, and Iris was one of the organisers of regular reunions until the 1990s.

Iris was born in Camberwell, south London, the daughter of William Catton, who had lost his leg during the first world war, and worked as a lift operator for the GPO, and his wife, Dorothy (nee Wilby), who was a housewife. She was brought up in Dagenham and went to Barking Abbey school, and started work aged 16 as a civil servant. At the outbreak of war, she was evacuated with the Ministry of Agriculture to Saint Annes on Sea in Lancashire. She joined the ATS in 1942.

After the war Iris married Alan Warne, whom she met at the Ministry of Agriculture, and became a very traditional housewife, working hard to make ends meet. She reused her honeymoon coat to make dungarees, a coat and a hat for me, her young son. She made cushion covers from fabric samples that were no longer needed by the local draper. She looked after everything in the house, including the decorating and gardening.

When Alan died in 1974, she determined to make the best of life, learning to drive and travelling all over the world, often to see old ATS friends who had moved to foreign parts. Iris joined Amnesty International and was a very active member until her 80s. She became a member of the Labour party and also went on anti-apartheid demonstrations. She had been a keen reader of the Guardian since 1954.

She is survived by me and by her grandsons, Philip and Oliver, and great-grandchildren, Darragh and Aoife.