Party leaders are planning to intensify the pressure by holding continued debates on the measure for two and three days a week to complete the Bill's Commons stages by the the end of May.
Without a natural majority for the Bill, the Government cannot run the rebels into the ground by forcing the debate to continue over a weekend, but they believe many Labour MPs and the Liberal Democrats will tire of voting with the rebels to allow it to be ratified by early July.
The decision to turn up the pressure came as the Prime Minister's office firmly denied potentially damaging speculation that Douglas Hurd, the Foreign Secretary, had told John Major he wanted to retire once the Bill had passed through the Commons.
'He has had no conversations with the Foreign Secretary about his future,' one source said. It was also denied by friends of Mr Hurd, 63, that he had told his constituency he would stand down at the next election.
Mr Hurd is unlikely to consider stepping down until summer next year when Mr Major has been advised to hold a wholesale reshuffle of the Government in time for the next election.
Ministers are anxious to kill the speculation about the departure of two of the architects of the treaty - the Foreign Secretary and his Minister of State, Tristan Garel-Jones, who has already announced his intention to stand down - because it will give added heart to the anti-Maastricht rebels.
Mr Major's closest advisers believe Mr Hurd is a powerful steadying influence on the Government which would be sorely missed until the Government's Maastricht and economic problems have been solved.Reuse content