A new group opposed to the increasingly cosy relationship between Mr Ashdown and the prime minister is being launched this weekend.

Those behind the Campaign for Liberal Democracy fear the party will lose its own image and be swallowed up by Labour. They want to call a special party conference to block the plans.

Mr Ashdown sparked uproar in his party last month when he proposed expanding the role of the Lib-Lab Cabinet committee, which is currently responsible only for constitutional issues.

The Liberal Democrat leader suggested the committee should work together in other areas.

Slipping behind

The Campaign for Liberal Democracy will be unveiled only hours after the publication of a poll carried out by Gallup for the Daily Telegraph, which showed support for the Liberal Democrats had slumped to 11% since Mr Ashdown's announcement.

Several Liberal Democrat MPs are angry at the lack of consultation and Mr Ashdown has faced stormy meetings with his parliamentary party and grass roots activists.

Last week, rebel Lib Dems showed the extent of their anger by joining the Tories in a rare vote against the Commons motion thanking the Queen for her Speech at the State Opening of Parliament.

Mr Ashdown, who was absent, opposed the move.

Seeking signatures

The Campaign for Liberal Democracy is seeking 200 signatures from conference delegates on a petition to trigger a special conference in January.

Simon Hughes...has set his face against the deal

The meeting will take place in the Bermondsey, south London, constituency of Simon Hughes - one of two MPs who voted against the new deal with Labour.

Mr Hughes will tell the meeting: "If we can recreate in other areas a process like that which delivered the Robin Cook-Robert Maclennan agreement on constitutional matters in bringing our Liberal Democrat policies into law and practice - then count me in."

But he said the party needed to "maintain - and indeed seek - clearly differentiated positions and a capacity robustly to oppose and vigorously campaign where we disagree".

'Willing to co-operate with Labour'

The campaign's founder, former Liberal Democrat councillor Donnachadh McCarthy, says: "We want to be able to co-operate with other parties, but outside the Official Secrets Act."

The existing joint body, as a Cabinet committee, is covered by the Act, meaning all details of its proceedings are confidential.

Mr McCarthy said he already had 90 signatures.

A meeting of the party's federal executive committee will discuss on Monday a ballot of the membership on Mr Ashdown's plan.

Tory Party vice-chairman Andrew Lansley said Mr Ashdown's position as leader was "becoming more untenable by the day".

He said: "Under Paddy Ashdown, the Liberal Democrats have become little more than a sub-committee of the Labour Party."