Pro-European Conservatives have warned Michael Howard not to panic in the face of a strong electoral challenge from the UK Independence Party.

Former Tory chancellor Kenneth Clarke was among those warning on Sunday against taking the party in a more eurosceptic direction.

"The great thing I would say is for heaven's sake don't panic in the face of a protest vote in the European elections at a time when a lot of the population are in a mood to protest against the state of politics anyway," he told Sky News' Sunday with Adam Boulton programme.

"To start haring after Robert Kilroy-Silk's vote would be a complete disaster."

And Lord Heseltine warned that there was "a steamroller" pushing the Conservative Party towards euroscepticism.

"The problem is there is a steamroller at work and the people within the party [who] made John Major’s life an absolute hell, they’re not going to be held back, they think they’ve got the bit between their teeth and their driving it on," he told GMTV's Sunday Programme.

"Michael’s trying to balance it but the momentum is there."

Former Tory chairman Lord Tebbit said support for UKIP would benefit Tony Blair's Labour.

"I think voting UKIP for a lot of Conservative voters is a way of firing a shot across the bows of the Conservative Party," he told the BBC.

"The trouble is that if they are not careful they could fire it a bit close to the waterline."

He added: "UKIP is in many ways an emotional spasm, much as I understand the views of the people. It is also a damn nuisance.

"What they are doing actually is to ensure that Blair will be representing us, if they have their way, in the Council of Ministers and not Howard. They should ask themselves which they want."

In the face of competing pressures, shadow local and devolved government secretary Caroline Spelman said the party's policies on Europe would remain unchanged.

"We want to remain in Europe. We'd like to see a more flexible Europe, less bureaucratic, less red tape," she told Sky News' Sunday with Adam Boulton.

"But that is very definitely the middle position, the centre ground, and I think that is the right place to be."

Tory 'trouble'

With the UKIP set to make a strong showing in the European elections, the Liberal Democrats said the Tories had got themselves into difficulties.

"It is going big trouble for Michael Howard and the Conservatives. There is no question about that," party leader Charles Kennedy told Breakfast with Frost.

"The Conservatives have spent years trying to run with the hare and the hounds where Europe is concerned and I think they are now going to be caught out by the voters and deservedly so."