Labour rebels set ambush for Blair

Labour MPs opposed to Tony Blair's backing for American-led military action against Iraq are preparing a Commons ambush that could lead to the biggest backbench revolt of his leadership.

The rebels plan to use a parliamentary procedure last employed 15 years ago to allow MPs a substantive vote on Tuesday's recall of the Commons.

The Government had hoped to contain a revolt with an adjournment debate at the end of which MPs can vote only on a technical motion ending the sitting.

Michael Martin, the Speaker, is being asked to rule on whether to allow a "manuscript amendment" to that motion, which would give the rebels their chance.

The procedure was last used by Tony Benn in 1987 in an emergency debate following revelations about the secret Zircon spy satellite.

Mr Benn, who is advising the rebels, said: "I believe that the Speaker has the discretion to allow a manuscript amendment. There are clear precedents." Leading rebels are pressing for talks with the Speaker tomorrow to discuss the move.

Lord Weatherill, the former Speaker, said MPs had a "very good case" for pressing for a substantive vote. He has voiced his "extreme surprise, not to say distress" that the Government is allowing MPs and peers just three hours to study the dossier of evidence against Saddam Hussein before this week's debates.

The looming ambush will alarm Hilary Armstrong, the Chief Whip, who has assured Number 10 that a mass rebellion can be avoided. Already 133 Labour MPs have signed an early day motion to signal that they believe action without UN backing to be unwise.

Mr Blair has been given a warning by Clive Soley, the former party chairman. "Things could get very serious for him if Britain takes part in US action not authorised by the UN," he said.

However, Donald Anderson, the chairman of the Commons Foreign Affairs Select Committee, who was briefed last weekon Iraq's weapons, said that his colleagues should not tie Mr Blair's hands with "gesture politics".