The poll, commissioned by two former Conservative MEPs, showed 11 per cent of the public would vote for a party that strongly backed a single European currency at the elections in June.
Mori found that support for the official Conservative Party would also be cut from 26 per cent to just 20 per cent, leaving it with no more seats than in 1994, when Labour swept to victory across the country.
By contrast, the party list system means that the pro- Europeans could win up to half a dozen seats. If Kenneth Clarke was their leader, their vote would rise to 19 per cent, the survey found.
The research was commissioned by the Pro-Euro Conservative Party, a group set up by the former Tory MEPs Brendan Donnelly and John Stevens after they resigned from the party over its hardline stance on the euro. They said William Hague could not survive such a "humiliation".
A spokesman for Conservative Central Office said: "This is just sour grapes from the sour grapes party. These two guys have no credibility because they couldn't get through the democratic selection process of the party." Other polls showed that the majority backed the Tory stance to see how the euro worked first.Reuse content