Support for the UK Independence Party (Ukip) has reached a new high of 15%, according to a poll published on Saturday night.
The anti-EU party's rating has risen by another percentage point in the past fortnight as its fortunes continue to rise, the Opinium survey for The Observer found.
Its support is almost double that for the Liberal Democrats, languishing in the same poll on 8%. Labour were on 39% with a 10-point lead over the Conservatives on 29%. All three main parties were unchanged from a fortnight ago.
Ukip leader Nigel Farage said today that 2012 had been a "remarkable year" for the party, which has seen its ratings rise from 4.5% just 12 months ago.
In a New Year message, he said Ukip's performances in a series of by-elections demonstrated that it was taking votes from Labour as well as the Tories.
"I'm particularly pleased to think back to the by-elections, especially the ones we had in Corby, Rotherham, and Middlesbrough," he said.
"What it showed was that despite the media obsession that Ukip is taking Tory votes - which of course we are - what those Northern constituencies showed is that Labour votes are coming to Ukip in real numbers too."
Opinium interviewed 1,965 British adults between December 21 and 27.
Labour MP Jon Cruddas, who is chairing his party's policy review for leader Ed Miliband, predicted that Ukip would have "a great 2013 and an even better 2014" when they could win the European elections.
In an article for the Sunday People, he said: "My hunch is that he (Nigel Farage) and Ukip will have a great 2013 and an even better 2014 when they may top the European elections," he said.
"For me politics was always about us (Labour) and them (Tories). Two teams, camps, gangs, crews, tribes - call them what you will - but basically left and right. I have never got the Liberals.
"But 2013 will be the breakthrough year of four-party politics - with Ukip the big winners."