She served as Minister for Culture, Sport and the Welsh Language in the Liberal Democrat/Labour Partnership Government from 2000 to 2003.

She was Health and Social Services; Equal Opportunities and Finance Spokeswoman for the Welsh Liberal Democrats during the Second Assembly.

She did not seek re-election at the 2011 Assembly elections,[6] saying she was "hopeful of a new role combining my love of campaigning with a slightly less hectic lifestyle.

"[7] Nigel Howells, her Liberal Democrat successor, was narrowly defeated by Jenny Rathbone.

In the early 1970, when a teacher at Spalding High School, Lincolnshire, Randerson lived on Guys Head Road in Lutton Marsh with her 25-year-old husband Peter, who worked for Nature Conservancy.

Randerson's funeral was held on 10 February 2025 in the National Museum of Wales and was attended by over 400 mourners.