British Prime Minister David Cameron has been rocked by the shock defection of one of his Conservative MPs to right-wingers UKIP.
Douglas Carswell is resigning from Parliament to trigger a by-election in which he hopes to become UKIP's first MP at Westminster.
It puts David Cameron under increasing pressure to respond to claims he is losing voters to the anti-EU, anti-immigration UK Independence Party.
UKIP performed well in recent local and European polls and hope to make a genuine impact in 2015's general election.
Olly Barratt reports from London.
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Mr Carswell says he wants to destroy a cosy Westminster 'clique' which he says won't deliver meaningful European Union reform and isn't providing meaningful democracy to Britons.
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But he insists it was a difficult decision.
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UKIP are sometimes compared to the Tea Party in the US.
Partly because they advocate smaller government, are anti immigration, and anti european union...
But partly also because Conservatives fear they will cannibalise the right-wing vote ahead of next year's general election - making it harder for Prime Minister David Cameron's party to secure a majority.
Hence the disappointment at Douglas Carswell's move from his former colleagues like Bob Stewart MP.
CLIP
The opposition Labour Party hopes it can capitalise - saying Douglas Carswell's defection proves the Conservatives are too divided to help Britons still struggling as the economy returns to health.
He will now fight a by-election in the hope of providing UKIP's first presence at Westminster - crucial to their credibility according to LBC political reporter Theo Usherwood.
CLIP
And UKIP leader Nigel Farage is clearly working to find other Conservatives to jump ship.
CLIP
UKIP did perform well in recent European and local elections, but seats at Westminster represent the ultimate prize.
Douglas Carswell brings that bottom line closer.
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