Ukip is set to win the European election on Thursday, narrowly beating Labour, according to the latest YouGov/The Sun poll.
The projection sees the Conservative Party relegated to the third place for the first time in the political history.
The survey predicts the Liberal Democrats will finish fifth, behind the Green Party.
Suggestions that Labour could enter a coalition with the Liberal Democrats after next year's General Election have been dismissed as "nonsense" by the man in charge of Labour's election strategy.
Douglas Alexander told the Scottish Labour conference that his party should hold the Lib Dems to account for their role in implementing policies such as welfare reform and a rise in tuition fees.
Alexander insisted that next year's election was "quintessentially winnable" for Labour.
"The Liberal Democrats want to pretend that they are the internal opposition to the Conservatives - they're not the internal opposition, they are the enablers of the Conservatives," he said.
"The reason David Cameron is sitting in Downing Street is because Nick Clegg is sitting next to him at the Cabinet table."
David Cameron's commitment to an in/out referendum on Europe is causing uncertainty and damaging investment in the UK, Business Secretary Vince Cable will warn today.
He will say that firms will "look elsewhere" to invest if access to the lucrative European market is jeopardised.
As Liberal Democrats gather for their spring conference in York, Mr Cable will also warn that Eurosceptics are putting the union with Scotland at risk by indulging in nationalist rhetoric.
He is expected to say, "How on Earth do you expect to persuade the Scots to ignore the siren voices of nationalism and separatism when you indulge in British nationalism and Euro-separatism?"
We understand that councillor Mike Hancock has resigned from the cabinet of Portsmouth City Council. The Liberal Democrat group will be selecting a successor for the planning, regeneration and economic development portfolio.
Mike Hancock continues to be a Portsmouth City Council councillor.
MP Mike Hancock has stepped down from the ruling cabinet of Portsmouth City Council.
He was suspended from the Liberal Democrat party last month after the leak of a report into allegations of sexual impropriety. He has denied the claims.
Mr Hancock resigned the parliamentary party whip last year, but was still sitting as a Lib Dem councillor until the local group ruled that his suspension meant it must strip him of the party banner.
The announcement of his resignation came hours before a meeting at which local Lib Dems were expected to decide whether Mr Hancock could retain his responsibility for regeneration and economic development while sitting as an independent councillor.
There are new questions tonight about why it took the Liberal Democrats so long to act against an MP accused of sexual misconduct.Read the full story ›
Following a private meeting this evening, Portsmouth City Council's Liberal Democrat group has said Mike Hancock will retain his seat on the council's cabinet.
He has been forced to stand as an independent councillor as he was suspended as a member of the party yesterday over claims of sexual misconduct, which he denies.
Explaining their decision, the group said: "This was decided because Councillor Hancock is best placed to fulfil the role of cabinet member for planning, regeneration and economic development."
As well as being a local councillor, Mr Hancock is also an MP for Portsmouth South.
ITV News has obtained a recording of the call a woman made to Nick Clegg's office in June 2011 following up on a letter she says she wrote three months earlier detailing allegations of sexual misconduct against the then Lib Dem MP Mike Hancock. He denies the claims against him.
In the call, she is heard saying: "I wrote to Nick Clegg back in March  and again in May and I still haven't had a courtesy letter."
Mr Clegg said today he "acted immediately" last year when he was told legal proceedings were being taken against Mr Hancock, who has been accused of sexual misconduct. He withdrew the party whip.
But the woman's solicitor told ITV News the party was made aware two years earlier, but nothing was done.
In March 2011, the alleged victim says she wrote a letter sent by recorded delivery to the Lib Dem leader's office. The party say they did not receive it.
Master Leslie, a High Court official, ruled disclosure of a report into councillor and former Lib Dem MP Mike Hancock was necessary so that the woman could feel she had "a fair hearing and a fair crack of the whip".
The report was written by Nigel Pascoe QC, who was asked by the city council to investigate the allegations for code of conduct proceedings.
The woman, a female constituent and a young mother, says Mr Hancock made "unwelcome sexual approaches". The leaked, redacted version of the report describes the account she gave as "credible".
The alleged sexual assault victim of MP Mike Hancock has won a bid to force a Lib Dem-led council to make available a full version of a QC's report about her accusations at a forthcoming civil court action.
Portsmouth City Council, where Hancock is a councillor, opposed the application for full disclosure of the report - a redacted version of which has already been leaked to the public.
But Master Leslie, a High Court official, ruled disclosure was necessary so that the woman could feel she had "a fair hearing and a fair crack of the whip".