A surge in support for the UK Independence Party has pushed it to within just two points of the Conservatives in a poll of voting intentions.
In a fresh headache for David Cameron, the survey by Survation showed a five-point slump for his party to a record low for the pollster of 24%.It was released as the Prime Minister wrote to Tory activists in a bid to smooth fraught relations with the grassroots over Europe and gay marriage.
Labour slipped one point to 35% but saw its lead over the Tories stretch to 11 points. The Liberal Democrats were down one point at 11%.
Survation's findings - based on 1,000 responses from an online panel - were calculated using a weighting system to reflect a number of factors including individuals' stated likelihood to vote.
David Cameron sent an email to members of his Conservative Party urging unity.
The Tory grandee Lord Howe has accused the Prime Minister of 'losing control' of his party as divisions over Europe come to the fore.
The Conservative Party has moved to head off a row with grassroots activists after a Tory ally reportedly described them as "loons".