Member Defections: Automatic By-elections

Debate between Charlie Dewhirst and Graham Stringer

Monday 16th March 2026 Westminster Hall

[Charlie Dewhirst]

I absolutely accept that there are many different voting systems that one could employ. Those with a mix between a party list and a constituency list create a two-tier system. What if one of the individuals on the party list were to defect? How would that be resolved? It would create a system even more challenging than the one we already have, which has a direct link between local people and their representative in the House of Commons.

One of my concerns is that making the continuation of that representation conditional on membership of a political party might start to weaken that link, which is a strength of the first-past-the-post system, but there is also the question of how it would be dealt with under the varied systems that we have across the range of PR options. Making representation conditional in that way would reduce Members to delegates of their party rather than individuals chosen to represent all their constituents, regardless of who they voted for—a point that is hugely important to us all. As we have discussed, the threat of a by-election could be used to silence Members who feel compelled by their conscience to go against their party.

As I just underlined, that is where the challenge about how to legally define an independent comes in. I am very sympathetic to the point that those who go independent should not face a by-election, but those who move from one established party to another should. The danger is that introducing mandatory by-elections would encourage Members to favour loyalty to the party over serving the interests of their constituents, particularly if they believed that those two things were in conflict.

Of course, defection is only one means by which a Member can change their party allegiance. While the petition speaks only of defection to another party, there are other methods: resignation, the withdrawal of the Whip, parties’ restructuring and so on are all means by which a Member may choose no longer to represent the party for which they were originally elected. I am sure that no Member believes that every Liberal Democrat should have been forced to stand in a by-election when the Liberals and the Social Democrats merged.

This is not the first time that the House has considered the issue of Members changing political allegiance. Previous Governments and Parliaments have wrestled with how to reconcile the independence of Members with the expectations of modern party politics, and in each instance they concluded that the independence of Parliament and its Members should not be constrained through major constitutional change.

[Graham Stringer]

I am rather surprised that nobody has mentioned that there is a constitutional precedent for by-elections when situations change. It used to be the case that when Members were appointed to the Cabinet, they had to face a by-election. In my city, Manchester, there was a famous by-election when Winston Churchill had to stand again, and he lost. I think that was just before the first world war. Then, a change of circumstances meant a by-election. It is a very serious change of circumstances if somebody changes political parties. I am interested in the hon. Gentleman’s view on that constitutional precedent.

[Charlie Dewhirst]

Things have changed over time, and I dread to think how many by-elections we might have had in recent years had we needed one every time someone was appointed to the Cabinet. I suspect that would have cost the public purse something quite significant. In the period of which the hon. Member speaks, there was a slower churn of those in the Cabinet, and there was not quite the political turmoil that we have seen in recent years, which would make such a situation challenging. It is a fair point, though, because the change of circumstance in that situation is far less than the change of circumstance of moving from one party to another.

As I have said, it is not the principle of the issue that concerns me, but the practicality. If Parliament did introduce legislation, it would have to be absolutely spot on and watertight, to ensure that it did not degrade the link between individual Members of Parliament and their constituencies, and that the party system did not become more empowered through any such change. That is my principal concern.

Our constitution and political system have drawn their strength from the respect we have for tried and tested convention, and we must always be wary of the danger of rushed constitutional change and unintended consequences. We need only to look at the recent past to see how previous attempts to enforce rigidity within our system have failed. Most notably, the Fixed-term Parliaments Act, which was seen as an important tool during the coalition Government, ultimately was viewed to have failed and was rightly repealed during the last Parliament.

The independence of Parliament and of an individually elected representative to do what they believe is in the best interests of their constituents is one of the longest-standing conventions in our political system. While I sympathise with the frustrations of the petitioners and understand their desire to see the proposed change enacted, I believe we would be unwise to surrender that independence.