Between 2001 and 2004, she served as Leader of the Liberal Democrats in the House of Lords and, from 2007 to 2010, as Adviser on Nuclear Proliferation to Prime Minister Gordon Brown.

Born at 19 Glebe Place[citation needed] Chelsea, London, Williams was the daughter of the political scientist and philosopher Sir George Catlin and the pacifist writer Vera Brittain.

[3][4] While she was an undergraduate and an Open Scholar at Somerville College, Oxford, Williams was a member of the Oxford University Dramatic Society (OUDS) and toured the United States playing the role of Cordelia in an OUDS production of Shakespeare's King Lear directed by a young Tony Richardson.

[5] As Minister for Education and Science (August 1967 – October 1969), Williams launched the first Women in Engineering Year in 1969.

[9] Her colleague David Owen recalled: "You'd watch her work a room at a local Labour event and she'd never start by smarming up to a regional leader or a councillor.

She'd settle down next to somebody whom she'd have no political reason to talk to – a solid party worker – and you'd watch this person's face light up.

When Wilson announced his resignation in 1976 and was succeeded by James Callaghan, she became Secretary of State for Education and Paymaster General, holding both cabinet positions at the same time.

In closing, she called on her colleagues to "think very hard before allowing the United Kingdom to withdraw from ... its major duty to the world—the one it will encounter, and then deliver, through the European Union".

[21] However, Lord Harries of Pentregarth reported that Williams "refused to sign up for the Society for the Protection of Unborn Children (SPUC), and generally kept a low profile on the issue of abortion.

"[22] Thursday, 21 June, 2007 She appeared on Question Time (TV programme) to discuss Salman Rushdie being honoured.

[23] Williams lost her seat (renamed Hertford and Stevenage) when the Labour Party was defeated at the 1979 general election.

[5] When, soon afterward, she was interviewed by Robin Day for the BBC's Decision 79 television coverage of the election results, both Norman St John-Stevas – the Conservative's Education Spokesman who had frequently clashed with her at the despatch box – and Merlyn Rees, the outgoing Home Secretary, paid tribute to her.

[25] Following the election, she hosted the BBC1 TV series Shirley Williams in Conversation, interviewing, in turn, a number of political figures, including former West German chancellor Willy Brandt, former Conservative prime minister Edward Heath and her recently deposed colleague James Callaghan.

Later that year, following the death of the Conservative MP Sir Graham Page, she won the Crosby by-election and became the first SDP member elected to Parliament.

At the 1987 general election, Williams stood for the SDP in Cambridge, but lost to the sitting Conservative candidate Robert Rhodes James.

Williams was a member of the Top Level Group of UK Parliamentarians for Multilateral Nuclear Disarmament and Non-proliferation, established in October 2009.

[34] Williams was originally opposed to the Cameron–Clegg coalition's Health and Social Care Bill, describing it as "stealth privatisation" during 2011.

[35] The government made some changes to the Bill, described by Williams as "major concessions",[36] but dismissed as "minor" by Guardian commentator Polly Toynbee.

[41] On 28 January 2016 she made her valedictory speech in the chamber, and on 11 February she officially retired, in pursuance of Section 1 of the House of Lords Reform Act 2014.

One is that we were both too caught up in what we were respectively doing — we didn't spend all that much time together; the other, to be completely honest, is that I'm fairly unjudgmental and I found Bernard's capacity for pretty sharp putting-down of people he thought were stupid unacceptable.

[46] She was a longtime resident of Hertfordshire, living in Furneux Pelham after she was elected MP for Hitchin, and moving to Little Hadham later in life.

See also: Williams was a main character in Steve Waters' 2017 play Limehouse, which premiered at the Donmar Warehouse; she was portrayed by Debra Gillett.