Ukip’s only MP, Douglas Carswell, has dramatically quit the party, declaring that – after the Brexit vote – it is a case of “job done”.
The Clacton MP will sit as an Independent, scotching – for now at least – rumours that he would rejoin the Conservatives.
The move follows months of bitter infighting in the party, which saw Mr Carswell trade verbal blows with both Nigel Farage and key Ukip donor Arron Banks.
Announcing the decision on his website, Mr Carswell wrote: “We have achieved what we were established to do – and in doing so we have changed the course of our country's history for the better.”
The statement made no mention of Ukip’s many feuds – instead insisting Mr Carswell was leaving “amicably, cheerfully and in the knowledge that we won”.
He told his constituents: “Like many of you, I switched to Ukip because I desperately wanted us to leave the EU. Now we can be certain that that is going to happen, I have decided that I will be leaving Ukip.
“I will not be switching parties, nor crossing the floor to the Conservatives, so do not need to call a by election, as I did when switching from the Conservatives to Ukip.
“I will simply be the Member of Parliament for Clacton, sitting as an Independent.”
A delighted Mr Farage told Sky News that Mr Carswell had “jumped before he was pushed - he should have gone some time ago”.
“Whilst he was sincere about Brexit he was never Ukip and constantly sought to undermine and divide us,” he said.
But the defection leaves Ukip in the grim position of having no MPs and with little prospect of gaining any, after recent by-election defeats.
The party won more than four million votes at the 2016 general election, but the first-past-the-post voting system left Mr Carswell as its only victor.
Paul Nuttall became leader last year, but lost a by-election in Stoke-on-Trent after admitting that claims on his website that he lost close friends at the Hillsborough disaster were untrue.
Meanwhile, Mr Farage called for Mr Carswell to be ousted, in a feud apparently motivated by the MP failing to push for the former leader to be given a peerage.
Mr Banks threatened to stand against Mr Carswell in Clacton in 2020 – then announced he had left the party in order to build a new political movement which he called Ukip 2.0.
Being left with no MPs will leave Ukip significantly weaker financially as well as politically, at a time when Mr Banks has pulled all his funding.
Mr Banks appeared to welcome the announcement, posting 'smiley face' and tick emojis on his Twitter page.
The party will lose more than £200,000 of Opposition ‘short money’ it currently receives, while being embroiled in rows with the EU about alleged mis-spending of funds in Brussels.
Politically, Ukip has been badly squeezed by the Conservatives’ move to the right under Theresa May – epitomised by her setting Britain on course for a hard Brexit.
A poll for The Times this month found that support has fallen to nine per cent, the first recent dip in the party's share of the vote into single figures.