Shirley Williams, co-founder of UK's Social Democratic Party, dies aged 90

LONDON (Reuters) - British politician Shirley Williams, who changed the country's political landscape in 1981 by quitting the Labour Party to co-found the Social Democratic Party, died on Monday aged 90.

Williams, who told the Guardian newspaper in 2015 her happiest memories were of living at her mother's countryside cottage during World War Two, left the Labour Party to form the SDP after becoming disillusioned with its leftist policies under leader Michael Foot.

The SDP merged with the Liberal Party in 1988 to form the Liberal Democrat party, which was the junior partner in a coalition government with the Conservative Party between 2010 and 2015.

Williams' mother was feminist writer Vera Brittain, author of the acclaimed First World War memoir 'Testament of Youth'.

As education minister between 1976 to 1979 in the Labour government of James Callaghan, Williams oversaw the growth of comprehensive schools and was known for her opposition to academically selective grammar schools.

She went on to become a Liberal Democrat peer in Britain's upper house of the parliament in 1993, becoming an adviser on nuclear proliferation to former Prime Minister Gordon Brown.

"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," Liberal Democrat leader Ed Davey said in a statement.

"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."

(Reporting by Elizabeth Piper; Editing by Toby Chopra)