The Conservatives could publish a draft bill before the next general election paving the way for a referendum on Britain's membership of the EU in the next parliament, a senior Cabinet minister suggested today.
Defence Secretary Philip Hammond ruled out introducing a bill for an in/out referendum in the current parliament - saying it would not get through the Commons.
But following the sweeping gains made by Ukip in last week's council elections, he said they had to do every thing they could to reassure voters that they would honour their commitment to give them a say in the next parliament.
He said that he believed the Conservative general election manifesto would include a clear commitment to legislate for a referendum as soon as they began the next parliament.
And he said that he would strongly favour the idea of publishing a draft bill ahead of the general election to underline their determination to see it through.
"We are looking at doing that and I think that would be a very good idea. I would strongly support the idea of publishing a draft bill ahead of the election," he told BBC1's The Andrew Marr show.
He accepted that voters were wary about Prime Minister David Cameron's commitment to renegotiate Britain's membership terms and then put the new settlement to a referendum after the general election.
"I understand people's scepticism. They are saying 'Yeah, yeah, that's the other side of an election. What can you do now to reassure us?"' he said.
"We should do everything we can to reassure people about our commitment. We should make it in very clear and unambiguous terms, including publishing a bill so that people can see exactly what will be in it."
However he said that any attempt to put it to the Commons before the election, due in 2015, would be defeated.
"We would not get a bill through Parliament in this parliament. The Labour Party doesn't want people to have a say on Europe. The Liberal Democrats would not support an in/out referendum on Europe," he said.
"I would imagine our manifesto will make an absolutely clear commitment to legislating for the referendum as soon as we begin the next parliament."
Mr Cameron is coming under increased pressure from senior Conservatives to stage a referendum on Europe before the next general election, with calls from Tory right-wingers for a "mandate referendum" as early as next spring.
Under their plan voters would be asked whether they supported Mr Cameron's plan to negotiate a new relationship between Britain and the European Union.
The new settlement could then be put to a second referendum after the general election in 2015 in line with the Prime Minister's existing proposals.
Former Tory leadership contender David Davis said that staging the first referendum to coincide with elections to the European Parliament next May would be "an absolute Ukip killer".
"It would massively reinforce the Prime Minister's negotiating hand and put some steel in his back," he told The Observer.
"He would be more likely to return from any negotiation with a good deal that would mean we stay in the EU."
Another Tory supporter of the plan, backbencher David Ruffley, said Mr Cameron needed a sharper message on Europe as many people were unaware of his referendum pledge.
"This would be a concrete vote showing that Conservatives are serious about getting a referendum. It is about focusing minds. This Ukip insurgency is real and it's serious," he told The Observer.
Meanwhile Ukip leader Nigel Farage made clear there could be no deal with the Conservatives as long as Mr Cameron was leader.
"Mr Cameron set the course of this coalition Government. His own leadership since 2005 has been pro-EU, pro open door immigration and pro building wind turbines all over our green and pleasant land. He is not going to U-turn on all of those things," he told The Andrew Marr Show.
However he suggested Ukip could form a pact with an alternative Conservative leader, although he did not consider it a priority.
"If he was removed and somebody else was put in place and wanted to come and talk to us and say 'Shall we find an accommodation?' we'd consider it, but it is not my priority," he said.
Speaking to Dermot Murnaghan on Sky News, Foreign Secretary William Hague said voters who supported UKIP should be treated with respect.
It was now up to the Government to get its message across more forcefully, he said, telling the programme ministers were doing everything they could to cut immigration, cap the welfare bill and bring down the deficit.
Mr Hague said it was "fair game" to claim UKIP's spending commitments "did not add up", adding that it was currently the "popular vehicle" for the protest vote.
He said the Conservative Party was unable to offer a referendum before the General Election because it was in a coalition with the Liberal Democrats but added Prime Minister David Cameron was prepared to look at ways to demonstrate the commitment to holding a referendum.
He said the Tory leadership had not ruled out asking MPs to vote on plans to hold a referendum but said that it would probably be defeated because the Conservatives did not have a majority.
Mr Hague said: "It's not a matter of changing course but it is a matter of pointing out that it is a choice at the next General Election between a Conservative Prime Minister and a Labour Prime Minister and we are doing our utmost to tackle the issues that people are concerned about in this country.
"A General Election is not an indulgence as a local election or by-election can be. It is a choice - do you want a Conservative government that is going on to carry on its important work and hold a referendum on the European Union or do you want a Labour government that would go back to all the things that went wrong under Gordon Brown?"
Mr Hague also insisted the Government would continue to meet its commitment to spend 0.7% of GDP on overseas aid but refused to say whether that would be put into legislation following the Queen's Speech on Wednesday.
He added: "I would get in to trouble if I pre-empted the Queen's Speech - it is only a few days away. But the main point is that irrespective of being for or against legislation on it, is, are we actually meeting our international commitment to spend the money?
"That's our international commitment. As far as I am concerned as Foreign Secretary, we have a commitment to the rest of the world that we will do that and we are going to be meeting that commitment."