Former Hitchin and Stevenage MP Shirley Williams - famed for breaking away from the Labour Party to form the SDP - has died at the age of 90.

The Baroness Williams of Crosby was one of the disenchanted ex-Labour cabinet ministers who became the Gang of Four founders of the breakaway and short-lived Social Democratic Party.

The Comet: Former MP for Hitchin and Stevenage Shirley Williams was made Baroness Williams of Crosby in 1993. She is pictured here after being awarded the Companies of Honour for services of political and public lifeFormer MP for Hitchin and Stevenage Shirley Williams was made Baroness Williams of Crosby in 1993. She is pictured here after being awarded the Companies of Honour for services of political and public life (Image: PA)

Affectionately known as Shilly Shally, Shirley Williams regarded herself as left-of-centre in Labour terms early in her political career, and came to be reviled by the party’s left who denounced her as a traitor to the movement after her defection to the SDP.

Born to Vera Brittain and Sir George Catlin on July 27, 1930, Williams was educated at the Summit School, Minnesota, where she was evacuated during the war, St Paul’s Girls School, London, and Somerville College, Oxford, where she met Bernard Williams, then a philosophy student and later a don.

The couple married in 1955 and they had a daughter, Becky.

Following a brief flirtation with journalism on the Daily Mirror, she threw herself into politics.

After a string of unsuccessful Labour candidacies, Williams eventually entered Parliament as MP for Hitchin (which then also included Stevenage) in 1964 until 1974. From 1974 until 1979, she then sat as Labour MP for Hertford and Stevenage.

She went on to hold a variety of titles throughout her political career, including Minister of State for Education and Science, Minister of State for Home Affairs, Prices and Consumer Protection Secretary, as Paymaster General and as Education Secretary.

Most notably, Williams - along with William Rodgers, David Owen and Roy Jenkins - she helped to form the SDP, a new party which claimed “unstoppable momentum” in its public support.

The party, of which she was president for a while, eventually collapsed amid recriminations and was moulded into the Liberal Party which, through a series of name changes, finally became the Liberal Democrats.

Meanwhile she had met distinguished US academic Professor Richard Neustadt, and the couple married in 1987. The following year she took up the post of Professor of Elective Politics in the John F Kennedy school of Government at Harvard University, so they could more easily be together.

She became a life peeress in 1993 and sat in the House of Lords as a Liberal Democrat and continued to remain deeply immersed in the political scene.

In the autumn of 2004, Baroness Williams retired as the Liberal Democrat leader in the House of Lords. Later, in 2010, she served as President of Stevenage Liberal Democrats.

Cllr Sharon Taylor paid tribute to the Baroness on Twitter, describing her as "a political hero, articulate, intelligent, selfless and with a passion for improving the lives of those she served."

Cllr Robin Parker, leader of the Liberal Democrats on Stevenage Borough Council, shared his memories of the former MP: “Shirley always kept up her links with Stevenage and always was willing to attend local events for the town, council or party. She was also President of Stevenage Liberal Democrats.

“She was at least partly responsible for getting me into politics nearly 60 years ago and I valued her advice and experience.

The Comet: Shirley Williams and Cllr Robin Parker, in the Ingelheim Lounge, Daneshill House, Stevenage in 2019Shirley Williams and Cllr Robin Parker, in the Ingelheim Lounge, Daneshill House, Stevenage in 2019 (Image: Robin Parker)

“Shirley Williams will be sadly missed by all of us - but her work and enthusiasm for Stevenage and the wider community will live on.

“Our deepest condolences go out to Shirley’s family and friends at this very sad time."

Cllr Sam Collins also shared his condolences: "Shirley Williams was a real inspiration, not just for us locally but for the whole Liberal Democrat party. Without her, the Lib Dems probably would not exist.

"Her loss will really be felt here in the areas she represented, and it makes us all feel that we have a duty to honour her memory by continuing the work she started."

“Shirley always kept up her links with Stevenage and always was willing to attend local events for the town, council or party. She was also President of Stevenage Liberal Democrats.”