The only UKIP MP is to quit the party.
Douglas Carswell, the only UKIP MP, who defected from the Conservative Party in 2014, is quitting UKIP to become an independent MP for Clacton.
He says the split is amicable and that he he is leaving because he feels his job is done at UKIP. Meaning that he is now certain that Brexit will be completed.
He is not crossing the floor of the Commons so no by-election will be needed.