Mr Blair, who was accused of acting like a "control freak" over the selection system for the European elections, will invoke the Parliament Act to force the Bill through the House of Lords after it is reintroduced on Tuesday in the Queen's Speech, but Downing Street has admitted that continued Tory opposition could wreck the timetable.
One leading Labour left- winger said: "It could mean a reprieve for some of the sitting MEPs who were deselected, and that means some of the Blairites like Michael Cashman may not get seats."
The delay in the legislation could also prove a mixed blessing for William Hague, the Tory leader. Some pro-euro MEPs who failed to get selected for the party lists will now try to win backing to fight their own seats.
John Prescott also wants the Tories to sink the controversial Bill on the European elections as a brake on the growing co-operation with Paddy Ashdown. The Deputy Prime Minister has made clear to friends that he would not be sorry to see the Tories slow the progress on the Bill, which Mr Ashdown needs to quieten his own critics. "He has never been in favour of coalition politics," said one of Mr Prescott's close allies.
The Bill would allow the elections to be fought on proportional representation, which will effectively give Labour euro seats to the Liberal Democrats. Mr Ashdown is under intense pressure to deliver the Bill as the pay-off for doing deals with Mr Blair.
Mr Prescott's concerns about the growing closeness between the Liberal Democrats and the Labour leadership are shared by other ministers. Jack Straw, the Home Secretary, was also hostile to concessions being made to Mr Ashdown over the European elections legislation.
The Liberal Democrat leader will be left exposed by the failure to deliver PR for the European elections. Activists warned last night that he could resign over the issue.
"I think it would be very likely he will have to resign if he loses on this issue," said Donnachadh McCarthy, a member of the Liberal Democrat federal executive.
Mr McCarthy, who opposes Mr Ashdown's strategy with Mr Blair, is a leading member of the Campaign for Liberal Democracy, which has started in the past three days to organise a special Liberal Democrat conference to call a halt to the extension of the scope of the joint Lib-Lab cabinet committee. The activists believe it will force the Liberal Democrats to curb criticism of the Government on areas such as health and education.
They believe Mr Ashdown will lose a vote at a special conference, which they are seeking to hold in the spring. They need 200 signatures among 3,000 conference delegates to force a conference, and are confident of achieving that.
Mr Ashdown may seek to avoid defeat at a party conference by putting the extension of the remit of the cabinet committee to a ballot of all party members, which he could win. But activists believe they have enough support to force Mr Ashdown to answer to a special conference, where further co-operation with the Government will be stopped.Reuse content