Baroness Platt of Writtle: Aeronautical engineer who went on to the House of Lords and chaired the Equal Opportunities Commission

Her engineering background drove the campaign that would be her longest-lived legacy: the Women Into Science and Engineering initiative

Platt: she was once described as 'the original Essex girl, but without the white stilettos' (PA)

Beryl Platt brought forward across the generations the determination that in the Second World War helped produce the Hawker Hurricane fighter aircraft, and applied that determination to the advancement of her sex in the 1980s and beyond. War needs gave her the chance to be an aeronautical engineer, working with the brilliant and difficult Sydney Camm, the Hurricane's designer, in the Hawker company's experimental flight test department at Langley, Berkshire; 40 years later she chaired the Equal Opportunities Commission.

As a life peer and frequent speaker in House of Lords debates into her nineties she championed the breaking-down of barriers to women pursuing careers once considered the preserve of men. Described as "staggeringly conscientious", the smiling young woman of the 1940s, pictured beside an ace pilot of the Hurricane, which made more "kills" in the Battle of Britain than the Spitfire, had already powered her way through studies at Girton College, Cambridge and won sceptical male colleagues over.

She had been trusted by a flight shed foreman to sit in the cockpit of a Hawker Typhoon, on the chocks, and she put the Napier Sabre sleeve-valve piston engine through its paces while he stood in front of the plane. Her diligence, during a stint in charge of the technical office of the experimental department while a colleague was away, so impressed the company's chief test pilot that he arranged for her £200 salary to be doubled. While studying in 1942 she worked for three weeks on the prolific Hurricane production line, which had 10 aircraft ready each day for flight-testing.

When she left Cambridge the novelist and scientist CP Snow, author of Corridors of Power and chairman of Cambridge University's appointments board, had advised her that Hawker, in preference to its rival Fairey, was best suited for her to do her war work with: "Brilliant, succinct careers advice," she noted, "which I took and never regretted."

After she had distinguished herself at Westcliff High School in Southend, a government bursary for student engineers had wooed her away from her intention to read mathematics, At Cambridge she was one of only five women among 250 men doing Mechanical Sciences; since women were not then awarded degrees, she emerged with a "title of degree" in 1943.

"It was very hard work, often 70 hours a week," she said of Hawker. "The atmosphere was intense... there was great camaraderie."

In 1946 she joined the research department of British European Airways to work on aviation safety: "Air safety was paramount... that was where my work lay.... passengers... in those days were more nervous."

In 1948, again looking to broaden her engineering experience, she prevailed on Sir Frank Whittle, inventor of the jet engine, to consider taking her on as his assistant, a job that would have to be created. The following year he responded: "The job is yours". But by then she had become engaged, with the wedding three weeks away, and dropping everything was out of the question. It was October 1949, and she left BEA: "in those days most women gave up their jobs on marriage, and I did too."

Platt was to face still greater changes with the deaths in quick succession of both her parents. It was at this time that she became a practising member of the Church of England.

Her father, Ernest Myatt, a former First World War prisoner of war, and once a heavy smoker, died in 1950 of lung cancer, and little more than a year later her mother, Dorothy, committed suicide. Platt and her husband, a friend from childhood, were to have a son, Roland, and a daughter, Vicky. Stewart Platt ran a textile business in Romford that made quilting, and was a keen yachtsman. On family sailing holidays Beryl fell prey to seasickness but stoically supported the adventures.

She found a new and challenging occupation when she took up local politics. By 1958 she was a member of Chelmsford Rural District Council, and by 1965 of Essex County Council. From 1971 she was the energetic chairman of the county's Education Committee, and between 1980-83 she was the council's vice-chairman.

She was once described as "the original Essex Girl, only without the white stilettos," and her reputation for making things happen reached Margaret Thatcher, and in 1981 she was elevated to the House of Lords, where she sat as a Conservative peer, and in 1983 she was appointed chairman of the EOC, established after the 1975 Sex Discrimination Act.

Her engineering background drove the campaign that would be her longest-lived legacy: the Women Into Science and Engineering initiative, known as "WISE". Wise's first chairman, she remained an attentive patron until her death. The campaign sprang from the recommendations of the 1980 Finniston Report into how to raise the status of engineering. Platt used her place on the Engineering Council, which was set up after the report, and her seat on the board of British Gas, where she made an ally of its chairman, the formidable Sir Denis Rooke, to obtain support.

She employed the same charm and perseverance that had prompted Sydney Camm to tell her when she left Hawker, "If you ever want to come back, you can," and had induced Frank Whittle to offer her a job, to enlist the help of industrialists such as Lord Tombs and Sir Bob Reid. She met Thatcher: "She was always very well briefed, and my goodness, I did my homework so I could answer her questions accurately and to the point."

Platt accumulated more than 20 honorary doctorates, and in 1988 was elected a Fellow of Girton. She was to outlive her younger brother James and her son Roland, both of whom died of pancreatic cancer, James aged 51 in 1982 and Roland aged 63 in December 2014.

Always a supporter of women priests, Platt lived long enough to know that the first woman bishop in the Church of England had been consecrated. In Lords debates she had long expressed the same sentiment about women's place in engineering: "In 100 years nobody will be able to understand why it took so long to be agreed."

Beryl Catherine Myatt, engineer and politician: born Leigh-on-Sea, Essex 18 April 1923; CBE (1978), cr. 1981 life peer; married 1949 Stewart Platt (died 2003; one daughter, one son deceased); died Hertfordshire 1 February 2015.