A by-election was held in the Bermondsey constituency in South London, on 24 February 1983, following the resignation of Labour MP Bob Mellish. Peter Tatchell stood as the candidate for the Labour Party, and Simon Hughes stood for the Liberal Party. Following a bitter campaign, the Liberals made huge gains and took the seat, with a majority of votes cast. Labour's vote fell from 63.6 per cent in May 1979 to 26.1 per cent as Tatchell came a distant second, while the Conservative candidate, Robert Hughes, managed only fourth place, losing his deposit. With a swing of 44.2%, the 1983 Bermondsey by-election remains the largest by-election swing in British political history.

Bermondsey was a borough constituency centred on the Bermondsey district of South London, England. It returned one Member of Parliament (MP) to the House of Commons of the Parliament of the United Kingdom. Elections were held using the first-past-the-post voting system.