Lord Howe, the former chancellor who brought down Lady Thatcher, in part over Europe, has criticised David Cameron's plan to hold a referendum on Britain's EU membership.
As the former Liberal Democrat leader Lord Ashdown said that the Tories were intent on taking Britain out of the EU, Howe said that parliament should have the final say over the UK's place in Europe.
The intervention by the two prominent pro-Europeans in a House of Lords debate on Europe came amid signs that coalition talks are close to breakdown over whether Britain will exercise its opt-out of EU police and criminal justice measures. The Guardian has learned that talks between Danny Alexander of the Lib Dems and Oliver Letwin of the Tories have effectively broken down over which of the 130 measures are regarded as so vital that Britain would immediately ask Brussels for permission to opt back into them.
Howe questioned Cameron's plan to hold a referendum by the end of 2017 if he wins the next general election. The former chancellor, who prompted Michael Heseltine to challenge Thatcher in 1990, told peers: "I would like to think I was wrong in suspecting that the prime minister's sudden conversion to the merits of a referendum is less about occupying the moral high ground of democratic consent than the search for a means to overcome the problems of internal party management."
Howe, who steered through the EEC accession bill as attorney general in Ted Heath's government in the early 1970s, added: "I don't believe a referendum is the way in which to address this question. Our own national parliament … not a widely consulted referendum, is the true source of democratic legitimacy and accountability."
Ashdown spoke of a "virulent little Englander" movement in the Conservative party, which "want out altogether". He added: "The difference between Britain and the rest is we are negotiating wanting to get out, while the rest of them are negotiating wanting to get further in."
The prime minister came under fire in the Lords as the US administration reiterated its belief that Britain should remain an active member of the EU. An adviser to Joe Biden, the US vice-president who is to visit Britain next week, said: "Obviously it's up to member states of the EU to make their own decisions. With respect to prime minister Cameron's speech, we obviously support his comments about the important role of the UK in the EU. We leave it to EU member states to have discussions."
Another US official said: "It's in our interest for there to be a strong UK in a strong EU."
The remarks echo the intervention by Philip Gordon, the US assistant secretary for European affairs, who said that the US wanted Britain to remain an active member of the EU.
The calls from the US came as coalition divisions over Europe risked scuppering negotiations over British co-operation on EU police and criminal justice measures. Both sides of the coalition agree that Britain should exercise a right, granted by the Lisbon treaty, to opt out of around 130 justice and home affairs (JHA) measures. But the Liberal Democrats will not sanction this mass opt-out unless the Tories agree to opt back in to key measures such as the European arrest warrant.
A source with knowledge of the talks has confirmed that "they are not making a great deal of progress; they are having to work through the package on a case-by-case basis".
The talks have been going on since October when the home secretary, Theresa May, told the Commons of the government's intention to exercise Britain's mass opt-out of police and criminal justice measures agreed between the 1992 Maastricht treaty and the 2007 Lisbon treaty under the banner of "repatriating British powers from Brussels".
A breakdown over the issue has serious implications for David Cameron's strategy on Europe, as this is one of the main matters on which he was hoping to secure demonstrable progress this side of the general election.
The row at the heart of the coalition's European strategy broke out on Thursday morning when the minister without portfolio, Ken Clarke, "announced" on BBC Radio 4's Today programme that ministers would opt back in to 30 of the 130 measures that were regarded as essential for crime and justice purposes.
However a senior Lib Dem source rapidly made clear that the veteran politician was jumping the gun: "There's a lot of common ground between Ken Clark and the Liberal Democrats on Europe, but he's getting ahead of himself on the justice and home affairs issue. No decision has been taken about how many measures the UK will opt back into. The question of whether to exercise the mass opt-out remains under discussion in government."
One of the big bones of contention in the Letwin/Alexander talks has been the future of the European arrest warrant which Tory right-wingers have put at the centre of their campaign for the repatriation of British powers from Brussels.
The Lib Dems, with the support of the police, have argued that there would be wide support across Europe to reform the workings of the arrest warrant.
The Eurosceptics argue that it is a waste of money to spend £30,000 sending a Pole back from London to Warsaw to face charges of 100 outstanding parking tickets.
But the Lib Dems have been arguing that this could be dealt with by simply raising the threshold for the seriousness of the crimes that would trigger the use of the warrant, and that the entire system did not have to be dismantled.
Sarah Ludford, the Lib Dems' home affairs spokeswoman in the European parliament, said in a Times letter on Thursday, that the arrest warrant had led to more than 300 paedophiles, murderers and rapists being returned to Britain to stand trial. She also said it would be folly to abandon the European-wide sharing of DNA and fingerprints found at crime scenes.
The only point of agreement the Lib Dems seemed to have reached with the Conservatives is that the plans for a European public prosecutor (which does not yet exist) should be abandoned.
