Members of Parliament (Change of Political Party Affiliation) Bill

Originating House

House of Commons

Parliament last updated

1 May 2012

In Plain English

AI-generated

May contain errors — check source documents for definitive information.

This bill would treat any MP who voluntarily changes the political party they described on the ballot paper at the time they were elected as having vacated their seat. In practical terms, a party switch would create an automatic vacancy, with the bill setting out how that vacancy would be dealt with.

Key Points

An MP who voluntarily changes their party affiliation from the one described on their ballot paper at election is deemed to have vacated their seat.
That creates a vacancy in the seat, with the bill setting out how it would be filled (through the vacancy process).
The provisions apply to all MPs and include related/connected rules as needed to implement the change.

Who is affected?

Members of Parliament (MPs)Voters/constituents in MPs' constituenciesPolitical parties and party membersThe House of Commons and its procedures

Generated 21 February 2026

Bill Stages

1st readingCommons

23 Nov 2011

2nd readingCommons

Committee stageCommons

Report stageCommons

3rd readingCommons

1st readingLords

2nd readingLords

Committee stageLords

Report stageLords

3rd readingLords

Royal Assent

Updates & Documents

News (1)

News - Members of Parliament (Change of Political Party Affiliation)

1 Jan 1970

The Bill failed to complete its passage through Parliament before the end of the session. This means the Bill will make no further progress.

Parliamentary Votes (0)

No recorded votes for this bill yet.