Rejected petition A by election will be triggered if a sitting MP switches political party.

If a sitting MP changes political party during the term of a parliament an
by election in that constituency is automatically triggered .

More details

It seems indefensible for an MP to change political party and not allow the constituents to have the opportunity to endorse or otherwise that change.

This petition was rejected

Why was this petition rejected?

There’s already a petition about this issue. We cannot accept a new petition when we already have one about a very similar issue.

You are more likely to get action on this issue if you sign and share a single petition.

You may wish to sign the following petition, which calls for similar action:

By-elections to be called automatically when MPs defect to another party
https://petition.parliament.uk/petitions/737660

We only reject petitions that don’t meet the petition standards.

Date submitted 15 January 2026
Get petition data (json format)

About petition data

The data shows the number of people who have signed the petition by country as well as in the constituency of each Member of Parliament. This data is available for all petitions on the site. It is not a list of people who have signed the petition. The only name that is shared on the site is that of the petition creator.