During the last months of the rogue Parliament, my own party experienced a great deal of this sort of thing. Every week petulant Remainer MPs would break-off to join some new party, some even managing to join two new parties within a week. No sooner had they ordered their new party letterheads than the name and logo would change again. At the time there was much angry agitation from Brexiteers that changing party after election should automatically trigger a by-election. I disagreed then and I disagree now.
What if their party change is overwhelmingly supported by their constituents? Why should everyone be put through the nonsense of a foregone conclusion? I'm much more in favour of a constituency's right to trigger Recall in such circumstances, provided the bar is set at the right height. Under FPTP a representative's seat is a matter for the voters, not for their angry ex-party officials. Under FPTP once elected they represent their constituents, not their party.
Now I'm not sure what the EP's rules are. UK MEPs are put in place on a party list system; if a party gets enough votes for 10 MEPs, the top ten names on the list get in. I suspect once they're in they're in - but this clearly doesn't suit for example parties structured like BrexitCorp™. I'm sure what Nigel would like, if numbers 4 and 7 don't suit, is to be able to sack them and substitute numbers 11 and 12 from the list. Happily, such control is inimical to democracy, even, I suspect, in Brussels.
