The Liberal Democrats will not rule out a referendum on staying in the European Union, Nick Clegg has confirmed.
"I am not going to draw a red line against having a referendum," the Deputy Prime Minister told Reuters.
His comments echo those he made during an appearance on ITV's The Agenda on Monday, he was asked if the EU referendum was a "red line" for the Liberal Democrats.
"I think we should have a referendum when we have to give away new powers to the European Union," Mr Clegg told the show.
David Cameron has said that a referendum would be a dealbreaker in any potential coalition tie-up, while the pro-European Liberal Democrats have resisted discussing the issue until this week.
Clegg strived to point out that he would not change his party's EU policy so close to the election, but his vocal stance on the issue this week suggests that he is open to a deal.
The consequences if you take a wrong turn could at its worst - and I'm not predicting this - mean that within a matter of years, two unions which are pivotal to the prosperity and way of life of everybody in Britain are lost.
"To be pro-European doesn't mean one is fearful of the British people," Mr Clegg added. "There are some circumstances in which a referendum should take place and I have always felt that.
EU migrants living in Britain should not be allowed to vote in a referendum on Europe, Nigel Farage has said.
Speaking on The Andrew Marr Show, the Ukip leader said his party could go into coalition with the Conservatives, as long as they offered an immediate referendum on EU membership under specific terms.
Speaking on BBC's The Andrew Marr Show, he said: "At the moment, there are four million or so EU citizens living in Britain that I do not think should be allowed to vote in that referendum."
During the interview, Farage also said his party would spend an additional £3 billion on frontline NHS services - using part of the £10 billion Ukip says it save by withdrawing from the EU.
The party says it also force migrants and tourists to pay for health insurance as a condition of entry, which it claims will save £2 billion of "wasted" money on "health tourism".
Bob Neil, Tory MP for Bromley and Chislehurst, has confirmed he will make another bid for an in-out EU referendum in law after coming third in the annual private member's bill ballot.
The former minister was the highest placed Conservative MP drawn at random, with Liberal Democrats Andrew George and Michael Moore securing first and second place.
Mr Neill, a strong supporter of the EU Referendum Bill, said: "One of the first votes I ever cast was on EU membership in the 1970s .Now as I pick up my bus pass I am getting the chance to work with colleagues to secure a referendum for the British people."
"Britain needs a new deal with Europe and the Conservatives have a plan for change in Europe - renegotiate, reform and put the deal to the British people in an in-out referendum by the end of 2017," he added.
David Cameron has said he is ready to invoke the Parliament Act to force through referendum legislation, after a previous bill introduced by Stockton MP Mr Wharton collapsed in January due to Labour and Lib Dem opposition in the Lords.
Downing Street has refused to wade into a row over the decision to potentially elect former Luxembourg premier Jean-Claude Juncker, after reports emerged that David Cameron warned Britain could leave the EU.
We are not commenting on this. It was a private meeting, a private conversation.
EU leaders should not bow to pressure from the minority in their decision of who to elect as European Commission chief, Jean-Claude Juncker has said, according to an advance extract of an article published in Germany's Bild am Sonntag newspaper on Sunday.
"Europe must not allow itself to be blackmailed," Luxembourg's ex-premier said, adding that a broad majority of Christian Democratic and socialist leaders in the European Council backed him.
He said he was in favour of getting "all of the other heads of government on board too" in the coming three to four weeks, and offered to hold talks on priorities for the next Commission.
German magazine Spiegel said David Cameron has warned German Chancellor Angela Merkel he may have to bring the UK referendum on EU membership forward if Jean-Claude Juncker becomes the European Commission chief.
The Prime Minister said he sees Mr Jucker, Mrs Merkel's candidate for the post, as too federalist and likely to damage his hopes of reforming Britain's EU ties.
The Prime Minister has "indirectly threatened" Germany's Angela Merkel that he would no longer guarantee British membership in the EU if European leaders elect Jean-Claude Juncker as European Commission chief, German magazine Spiegel said.
David Cameron said that if Mr Juncker became the EU Commission's president, the UK government could be destabilised to the extent that an "in-out" referendum would have to be brought forward, Spiegel reported.
The European Commission president is selected by EU leaders but must be approved by the EU parliament where Eurosceptics from the right made gains in last week's election.
Nigel Farage has claimed Ed Miliband will be forced to back calls for an automatic EU referendum if Ukip outperform Labour in the upcoming European elections.
The Ukip leader told the BBC's Andrew Marr Show there was growing Labour backbench support for holding an in-out referendum, despite the Labour leadership clearly opposing it.
Mr Miliband told the same show that Labour would back a referendum if powers were transferred from Britain to the European Union, a situation he judged "unlikely but ... possible".
But he said debating whether we should exit the EU was not "a priority" among his plans to govern Britain.
Mr Farage, meanwhile, refused to be drawn on whether he would run as an MP at the next General Election after opting against a candidacy in the upcoming Newark by-election.
"I want Ukip to win the European Elections," he said. "We'll talk about the General Election afterwards."