Petition · Cabinet Office
By-elections to be called automatically when MPs defect to another party
Closed
129,335 signatures
What the petition asks
When an MP decides they want to defect to another party a by-election should be automatically triggered to allow the constituents the opportunity have their democratic right to agree or not with their elected official.
Regardless of political views I believe you vote for both the individual candidates and their stance on issues and the more general direction and policies of the party they stand for. When an MP decides that they no longer wish to be a member of the party they stood for when you voted for them the electorate should have the opportunity to also change their mind by voting in a by-election.
Government response · 9 February 2026
There are no plans to make changes to the current constitutional arrangements, whereby voters elect individual candidates, and not the political party they represent.
It is an established constitutional principle that at UK General Elections, voters cast their vote for individual candidates, and not the political party they represent.
When a Member of Parliament (MP) decides to change their party affiliation, it is for the MP to decide whether to continue to sit in the House of Commons (as a representative of their new political party or as an independent MP) or to stand down from their seat to trigger a by-election and, if they wish, seek re-election.
There are no plans to make changes to the current arrangements.
Cabinet Office
When a Member of Parliament (MP) decides to change their party affiliation, it is for the MP to decide whether to continue to sit in the House of Commons (as a representative of their new political party or as an independent MP) or to stand down from their seat to trigger a by-election and, if they wish, seek re-election.
There are no plans to make changes to the current arrangements.
Cabinet Office
Debate in Parliament
MPs debated this petition on 16 March 2026.
Timeline
| 4 Sep 2025 | Petition opened for signatures |
| 17 Jan 2026 | Passed 10,000 signatures, requiring a government response |
| 22 Jan 2026 | Passed 100,000 signatures, qualifying for a parliamentary debate |
| 10 Feb 2026 | Government responded |
| 4 Mar 2026 | Closed to new signatures |
| 16 Mar 2026 | Debated in Parliament |
Key facts
Signatures
129,335
Status
Closed
Department
Cabinet Office
Opened
4 Sep 2025
Closed
4 Mar 2026
Response
9 Feb 2026
Debated
16 Mar 2026
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Source: the official petition page. Last checked 26 Jul 2026.