The Dudley by-election of 1921 was held on 3 March 1921. The by-election was held due to the appointment of the incumbent Coalition Conservative MP, Arthur Griffith-Boscawen, as Minister of Agriculture. It was won by the Labour candidate James Wilson. It was one of only eight ministerial by-elections in the UK to not be retained by the incumbent.
References
Dudley by-election, 1921 Wikipedia(Text) CC BY-SA