Tony Blair has been warned that he will have to rely on Conservative votes to press through plans to be announced today for the replacement of Britain's nuclear deterrent.
Mr Blair is likely to face one of his last parliamentary showdowns when MPs vote on the plans next year.
Analysis of parliamentary motions suggest that enough MPs are strongly opposed to replacing Britain's ageing Trident nuclear missile system to wipe out Mr Blair's working majority, forcing him to fall back on the Opposition when MPs vote on the proposals.
Mr Blair will unveil the long-awaited White Paper on nuclear defence this afternoon in a personal statement to the Commons.
It is expected to recommend that Britain replace Trident with a new submarine-launched nuclear ballistic missile system, when the current deterrent reaches the end of its life around 2024. It is likely to float the idea of reducing Britain's stockpile of nuclear warheads and include the possibility of cutting the country's fleet of nuclear missile submarines from four to three to minimise the anticipated £30bn cost of the new deterrent.
However, 63 Labour MPs have signed parliamentary motions calling on the Government not to replace Trident, and many more have signed motions calling for a full debate about Britain's nuclear deterrent before the vote. Fifty-three Labour backbenchers signed a motion in February warning that replacing Trident would breach the Nuclear Non-Proliferation Treaty, while 55 signed another motion last year calling on ministers to "abandon" any plan to replace the missile system.
The strength of opposition was shown by a poll of MPs yesterday which found 39 per cent of Labour MPs - and 31 per cent of MPs from all parties - believe Britain should not maintain a nuclear deterrent "for the forseeable future".
The poll by Communicate Research found 36 per cent of Labour MPs believed that "the international security outlook makes a UK nuclear deterrent unnecessary."
Professor Philip Cowley, of Nottingham University, the leading analyst of backbench rebellions, said 117 Labour MPs had signed motions about Trident, although many simply called for consultation and a vote on the issue. But he warned: "I cannot see a way this will get through if they don't rely on opposition support."
Gordon Prentice, the Labour left-winger, said he planned to send a letter to Labour's national executive after today's statement demanding a full consultation with all constituency Labour branches and trade unions. He said: "There is no doubt that the Government will have to rely on Conservative votes. There are two issues, the substantive question of Trident itself and the process. What is the point of having a consultation if there is a predetermined outcome."
Peter Hain, the Northern Ireland Secretary, has been pressing for Labour officials to hold a special meeting of the party's National Policy Forum to discuss the issue.
Jon Cruddas, the Labour deputy leadership hopeful, will today launch a consultation run by the left-leaning Compass group to feed views from the party to MPs before the final vote.
The White Paper will be approved by the Cabinet this morning and start a three-month consultation .
Anti-nuclear campaigners will deliver an "alternative" White Paper to 10 Downing Street today.Reuse content