British Prime Minister Tony Blair could face one of the biggest rebellions by the Labour Party in a decade in power today when the House of Commons votes whether to renew Britain's nuclear arsenal.
As many as 100 Labour MPs could reject Blair's plan to spend up to £20 billion pounds on three or four nuclear-armed submarines to replace the ageing Trident system.
It would be the biggest rebellion against Mr Blair since nearly 140 Labour politicians voted in 2003 against war in Iraq and Mr Blair's biggest setback on a domestic issue since he came to power in 1997.
Mr Blair, who has a majority of 67 in the 646-seat Commons, is expected to win with the help of the Conservatives who have said they will back the replacement.
Labour MP Michael Meacher
The prime minister, due to step down in a few months, argues Britain must retain nuclear weapons because new threats from Iran, North Korea or nuclear terrorists make it dangerous to abandon them.
Opponents say there is no need for the weapons now the Cold War is over and Britain will set a bad example to countries such as Iran and North Korea by insisting on keeping them.
Critics say the money could be better spent and complain they are being rushed into a decision by an outgoing prime minister eager to create a legacy.
The government argues design and construction of new submarines will take so long that it must act quickly to have a replacement ready when the existing nuclear submarines go out of service in about 2024.
"Our decision could well be the hinge point between real impetus towards stopping proliferation or a trigger leading to a cascade of further proliferation," Michael Meacher, a left-wing Labour MP who will challenge for the party leadership when Mr Blair steps down, said in a statement.
A deep hostility to nuclear weapons runs through the Labour Party, which espoused unilateral nuclear disarmament until the late 1980s. Almost two-thirds of Labour MPs who took part in a poll released on Sunday opposed the plan.