LONDON • Britain's anti-immigration, anti-EU UK Independence Party (Ukip) has lost its only MP.
Mr Douglas Carswell quit the party on Saturday, days before Prime Minister Theresa May was to launch the formal Brexit process.
Mr Carswell defected from the ruling Conservative party in 2014 to become the only Ukip member of the 650-seat House of Commons. But he has long been at odds with the party's founder, Mr Nigel Farage.
In a blog post, Mr Carswell said Ukip had played a leading role in last year's referendum vote to leave the European Union but it was "job done".
"I will leave Ukip amicably, cheerfully and in the knowledge that we won," he wrote, adding that he would continue to serve as an independent lawmaker.
His announcement came just days before Mrs May plans on Wednesday to trigger Article 50 of the EU's Lisbon Treaty, starting a two-year countdown to Brexit.
Mr Farage last month asked Mr Carswell to step down, accusing him of being soft on immigration - a key issue in the Brexit campaign.
"Carswell has jumped before he was pushed," Mr Farage said in a statement. "While he did want to leave the EU, he was never Ukip and sought to undermine us. He should have gone some time ago."
Ukip leader Paul Nuttall said his departure "will make no difference to my ability or focus on delivering the reforms I promised" to move forward.
Ukip has been plagued by infighting since the Brexit vote and has struggled to build a platform beyond its core message of euroscepticism and opposition to mass immigration.
Last month, it failed to win a by-election in Stoke, the city that recorded the highest vote for Brexit last year and which had been viewed as the party's best hope to win a second MP.
Mr Matthew Goodwin, an expert on the political right, tweeted: "Maybe Carswell senses the changing wind?"