The Warrington by-election, 1981 was held on 16 July 1981. The by-election was caused by the appointment of Thomas Williams, Labour Party Member of Parliament (MP) for Warrington, as a High Court Judge. The Conservative Party had taken second place in Warrington in 1979, with 28.8% of the votes cast. In mid-term government and behind in the polls, they did not expect to advance and stood Stanley Sorrell, a London-based bus driver, and unusually for a Conservative, an active trade unionist.