This list notes when a Member has changed allegiance from one political party to another or decided to sit as an independent MP. Instances of Members losing or resigning a party whip are also noted.
MPs' changes of party allegiance in the House of Commons since 1979 (110 KB , Excel Spreadsheet)
No, by-elections are not automatically triggered if an MP changes his or her party affiliation although an MP may choose to stand down and fight the ensuing by-election under a new party label or as an independent Member.
Information on the role of the Government and Opposition whips in the management of parliamentary business can be found in the Commons Library briefing on the Whips’ Office.
This series of publications contains data on various subjects relating to Parliament and Government. Topics include legislation, MPs, select committees, debates, divisions and Parliamentary procedure.
Due to the difficulties in compiling a comprehensive list of all floor-crossings, whip withdrawals and whip resignations, this list cannot be guaranteed to be definitive.
We are always happy to hear of any additions or amendments to the list. Please email papers@parliament.uk with any comments.
We also welcome suggestions for new lists.
MPs' changes of party allegiance in the House of Commons since 1979 (110 KB , Excel Spreadsheet)
The 2024 elections accentuated a three-way split in the French National Assembly, leading to further instability. The government appointed in September had fallen by the end of the year.
This list identifies all the women who have ever been elected to the House of Commons. They are reported by election, then in the order in which they were sworn in.
This paper looks at the role of the Parliamentary Ombudsman, and recent proposals for its reform.
