The short-term electoral consequences and longer term political damage... could be severe

Kenneth Clarke

He has voiced his concerns because of moves to deselect the pro-European former minister, Ian Taylor, in his constituency of Esher and Walton.

Local members are due to meet on Monday to decide whether to drop Mr Taylor, their MP for 13 years, as candidate for the next general election.

The Tory leadership has expressed its disapproval of the petition, insisting Tory MPs should be free to express their individual opinions.

Mr Clarke warned the Esher and Walton meeting "could be a key occasion in determining the future nature of the Conservative Party".

"The short-term electoral consequences and longer term political damage that would flow from attempts made by the more extreme Euro-sceptics to force a narrow nationalism onto our MPs could be very severe," he wrote.

'Political damage'

Party divisions over the European Union were a factor behind the Conservatives' defeat at the general election, with the former chancellor one of those favouring closer ties.

The Independent on Sunday said Mr Clarke told a Westminster reception last week he would be ready to stand against party leader William Hague if there were a Conservative leadership contest after the next election.

Mr Clarke ran for leadership in 1997 but was defeated by Mr Hague.

With shadow chancellor Michael Portillo stating he had no intention to run for party leader earlier in the week, it could leave the door open for Mr Clarke to try again.

Michael Portillo: No ambition to be Tory leader

Mr Portillo was seeking to draw a line under heavy speculation that he had become disillusioned with politics and was considering leaving Westminster.

In a statement he insisted he was committed to the Tories and politics but had no ambitions to lead the party.

Instead, he said, his aim was to become chancellor following a Tory victory at the next election.

Labour party need not go to the polls before mid 2002, but it is widely thought Prime Minister Tony Blair has pencilled in 3 May 2001 as the date of the next general election.

The Conservatives enjoyed a sharp upturn in popularity in September, creeping just ahead of Labour after languishing well behind since losing office in May 1997.

But in recent weeks they have slipped back again, with a recent Mori poll for The Times putting Labour 15 percentage points ahead of the Tories.