She 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.
Throughout her political career, both in the Labour Party and subsequently the SDP and then the Liberal Democrats, Williams was a passionate pro-European.
At one time, there was serious talk of Williams becoming Britain’s first woman Prime Minister, but it was not to be. She herself outwardly showed no ambition in this direction and she was anyway viewed, in political terms, more as a perpetual lieutenant rather than a general.
Liberal Democrat leader Ed Davey said: “This is heartbreaking for me and for our whole Liberal Democrat family.
“Shirley has been an inspiration to millions, a Liberal lion and a true trailblazer. I feel privileged to have known her, listened to her and worked with her. Like so many others, I will miss her terribly.
“Political life will be poorer without her intellect, her wisdom and her generosity. Shirley had a limitless empathy only too rare in politics today; she connected with people, cared about their lives and saw politics as a crucial tool to change lives for the better.
“As a young Liberal, Shirley Williams had a profound impact on me, as she did on countless others across the political spectrum. Her vision and bravery, not least in founding the SDP, continues to inspire Liberal Democrats today.
“Rest in peace, Shirley. My thoughts and prayers are with your family and your friends.”