The UK Independence Party is enjoying its "highest level of support" among voters, according to the latest survey, as the Prime Minister prepares to make a keynote speech on Britain's role in Europe.
Polling company Ipsos Mori's January Political Monitor found 9% of those certain to vote in the General Election said they would put a cross next to Ukip, a two point rise since last month.
It placed Nigel Farage's party ahead of the Liberal Democrats, who fell a point to 8%.
Mr Farage today said David Cameron, who will speak in the Netherlands on Friday, was trying to "deflect" the issue of Europe for five years but predicted that the debate would be decisive in securing UK's exit.
The eurosceptic MEP told the European Parliament: "The longer this debate goes on, the more likely the UK is to leave the European Union, and this debate will not stop."
Centrica's boss warns an EU referendum risks "total destabilisation" for businesses; the Next chief suggests that view is "scaremongering."
There will be sympathy, yes. But will they agree with him? No.
Conservative MPs said their "achievable" proposals to change Britain's role in Europe do not represent an ultimatum to the Prime Minister.