The former Tory chancellor Kenneth Clarke launched an extraordinary attack on Iain Duncan Smith yesterday, arguing that his "extreme" Eurosceptic views would make the Conservatives unelectable.
Mr Clarke claimed the Conservative leader wanted to withdraw from the European Union in its present form and was deliberately "raising this bogeyman of the superstate".
His intervention overshadowed the first major speech by Mr Duncan Smith on Europe since he became leader and threatened to shatter unity in the Conservative Party.
In a scathing personal attack, Mr Clarke characterised him as a fringe extremist on Europe who was out of step with the policy of the last Tory government. He warned that such an "extreme" position would not win over floating voters or help the Conservative party beat Labour at the next general election.
"The party that used to win, that was in government, did not have these opinions," he said at a lunch with political journalists. "It was opinions of this kind that made Iain such an isolated rebel."
Mr Clarke attacked a speech in Prague by Mr Duncan Smith yesterday in which he said there was a choice between "a centralised and federalist Europe" or "a partnership of sovereign states".
"Iain should not pretend this speech is not a call for withdrawal from the European Union," he said. "What Iain is suggesting is a complete change in the nature of the European Union. He wants to get back to a free-trade area and little more."
Mr Clarke, who stood against Mr Duncan Smith for the Tory leadership, said he was "going back to all the old extreme positions of declaring we must leave the European Union in the form that has existed since it was founded".
In his speech in Prague, Mr Duncan Smith said claims that the Conservative Party wanted to leave the European Union were a lie. "The truth is that we are as committed to building a New Europe of sovereign democracies as we are opposed to a United States of Europe," he said.
The Tory leader said he had a "positive vision" for Europe which was "founded on co-operation between nations - not soulless supranational institutions".
His "vision" was for a "Europe of national democracies trading freely with each other and committed to freedom and democracy around the world".
He said Britain's national veto should be protected "on issues of fundamental importance".
An EU constitution, he argued, would "lead inescapably to ever more power being transferred to Brussels - a blueprint for a United States of Europe in all but name".
He pledged that under the Conservatives Britain would not join the euro.
"Businesses want to plan ahead, voters want honesty," he said. "Both can be sure that, with a Conservative government, Britain will not join the euro."
Mr Duncan Smith said his vision was of "a Europe of free nations, sovereign and freedom loving, a Europe of democracies."
He said he wanted to see "strong national parliaments and vigorous local politics", adding that "the existing institutions of the European Union are not meeting today's challenges".
The Tory leader also criticised the EU's security and defence policy and praised Nato. "Nato guarantees national sovereignty," he said. "The EU constitution will subjugate it."
Back at Westminster, Eric Forth, the shadow Leader of the Commons, admitted that the Conservative Party was "still suffering from the backlash from office".
"We are recovering. We are still working off that 18-year memory," he said. "But it's taking its time."Reuse content