British Prime Minister Tony Blair tonight won House of Commons backing for his plans to replace Britain's Trident nuclear deterrent, despite the biggest Labour Party backbench revolt since the Iraq war.
With the Conservative Party backing the British Government, a motion supporting Trident renewal was passed comfortably by 409 votes to 161, a majority of 248.
An amendment tabled by rebel Labour MPs to delay a decision was defeated by a similar margin of 413 to 167 - a 246-vote majority.
However, the vote left the Labour Party bitterly divided with 95 MPs supporting the rebel amendment and 88 opposing the Government on the main motion.
The rebels immediately vowed to carry on their campaign against Trident renewal, leaving Chancellor Gordon Brown - if as expected he succeeds Mr Blair as prime minister - with the prospect of more battles ahead.
Left-winger John McDonnell, who has said that he intends to run against Mr Brown, said the leadership was out of step with the party, insisting: "The scale of this rebellion clearly demonstrates that the prime minister has completely misjudged the overwhelming mood in the party. This is only the beginning of the campaign against Trident's replacement."
Armed forces minister Adam Ingram, however, denied that the vote had been a setback for the Government, telling Sky News: "I don't see this as a bloody nose. I see this as a very considered opinion by the House of Commons. This was a debate for the nation, not the Labour Party alone."
As well as the familiar Government critics, the rebels included former home secretary Charles Clarke and Andrew Smith, another ex-Cabinet minister and close ally of Mr Brown.
Earlier two more ministerial aides - Stephen Pound, the parliamentary private secretary (PPS) to Labour Party chairman Hazel Blears, and Chris Ruane, the PPS to Northern Secretary Peter Hain - resigned in protest.
In the Commons, Mr Blair defended the decision to retain Trident and said it was essential a decision to begin work on the design of a new submarine fleet was taken now.
"I think that is essential for our security in an uncertain world," he told MPs. "We can't put this decision off. We have to take it now."
Mr Cameron said that the Conservatives were supporting the Government on Trident replacement "in the national interest".
"In a dangerous and uncertain world, unilateral nuclear disarmament has never been and will never be the right answer," he said.