Heseltine says Tories would sign up for euro

Lord Heseltine has risked antagonising the Conservative leadership by predicting that a Tory government led by Iain Duncan Smith would take Britain into the European single currency.

The former deputy prime minister also forecast the "centre" of the party would support a "yes" vote in a referendum, leaving its leadership on the margins of the argument. His comments – his most outspoken on the issue since the last election – will put new pressure on the uneasy truce in the party over the single currency.

In an interview to be broadcast tomorrow on GMTV, Lord Heseltine said he believed "on balance" that a vote on membership would take place before the election and insisted he would not be gagged on "the transcending issue of our time" in a referendum campaign.

He added: "I think the leadership of the Conservative Party today will find itself aligned with the extreme left of the Labour Party campaigning for a 'no' answer. The centre of the Conservatives will find itself aligned with the Liberal Democrats and the Government arguing for a 'yes' result." He said he would vote Tory at the next election despite Mr Duncan Smith's hardline stance on the single currency. And Lord Heseltine predicted: "If he became prime minister, he would change his mind, in my view, because the pressures and the logic would become unanswerable."

He also accused Tony Blair of an "opportunist short-term approach" to the single currency. He said: "It's like shoving a thermometer into the patient's throat, and if the temperature has gone up then change the policy."

Twenty-nine MPs from three parties have signed a Commons motion condemning the cinema advertisement likening supporters of the single currency to Adolf Hitler.