THE DEPUTY leader of the Commons Nigel Griffiths resigned from the government on Monday in protest at plans to renew the UK's Trident nuclear weapons system .. the day after the Sunday Herald exclusively revealed his plan to defy Prime Minister Tony Blair.

Griffiths said he resigned "with a heavy heart but a clear conscience" ahead of Wednesday's House of Commons vote on the plan.

He added: "I intend to make a personal statement in the House of Commons to colleagues and it is only right that they hear the reasons first."

The Sunday Herald had reported that Griffiths told a meeting of constituents in Edinburgh last week that he would not back Tony Blair's £100 billion bid to renew the weapon. He said he would vote "with his conscience" and he expected to be out of a job as a result.

The resignation of Griffiths is the most senior casualty so far of the argument over Trident. Livingston Labour MP Jim Devine has also said he would step down as private parliamentary secretary in protest over Trident.

Reports have suggested that as many as 140 Labour MPs are planning to vote against the white paper to replace Trident warheads, carried by nuclear submarines based on the Clyde. That could leave the government dependent on the support of Conservative MPs to win the vote.

At a meeting in Morningside in Edinburgh last Saturday, Griffiths left little room for doubt about his position. "He wasabsolutelyclearhecouldnot support the white paper and that he will vote with his conscience," said Rachel Howell, a local resident who was present. "I thought it was gutsy of him."

David Somervell, who also attended the meeting, added: "Nigel said he would be out of his ministerial post within days'. He felt the issue was clear and acknowledged that many of his constituents sought an end to UK nuclear weapons."

Griffiths told the meeting he could see no purpose in proceeding with a weapon for which there would be no use in 15 years. And he indicated he would be reluctant to support LibDem and SNP amendments in this week's vote.

Griffiths has also emailed constituents saying he did not intend to vote for the replacementofTrident.Oneofthe branches of his constituency Labour Party has come out against Trident.

Nigel Griffiths was first elected as Labour MP for Edinburgh South in 1987, and has held a series of ministerial posts in the Department of Trade and Industry over the past 10 years. Seen as an ally of Gordon Brown, he has been deputyleaderoftheHouseof Commons under Jack Straw since 2005.

Jim Devine, the successor to the late Robin Cook as MP for Livingston, on Saturday confirmed a report he was planning to resign as a ministerial aide over Trident. He is parliamentary private secretary to Rosie Winterton, health minister.

Devine has a history of campaigning against nuclear weapons and took part in Scotland's Long Walk for Peace last September. He addressed a rally in his constituency as part of the walk from Faslane to the Scottish Parliament.

Trident also prompted the resignation of a minister in the Scottish Parliament. In December, Edinburgh North and Leith MSP Malcolm Chisholm quit as communities minister after voting with the SNP after a Holyrood debate on Trident.

Further evidence of divisions in Labour ranks comes from a report arguingstrongly against Trident, endorsed by the Scottish Trades Union Congress and the Labour green group, the Socialist Environment and Resources Association.

The funding required for Trident could put 3000 public service jobsatriskinScotland,thereport argues. It also dismisses claims 11,000 jobs could be lost if Trident was not replaced, saying the figure would be less than 1800.

The report, called Cancelling Trident, says more than 40,000 defence jobs have been shed in Scotland since 1990. "For the decommissioning of Trident it is proposed that an Arms Conversion Agency be established to oversee the creation of alternative employment," it says.

Labour's split over nuclear weapons have been seized on by SNP leader Alex Salmond."TonyBlairisliving in a fantasy world if he thinks it makes sense for Labour to have a debate on Trident at thestartoftheScottishelection campaign," he said.

"Most of his own MPs in Scotland oppose a Trident replacement, as well as the overwhelming majority of the Scottish people. Tony Blair's obsession with his legacy - including trying to foist nuclear weapons on Scotland before he departs - has blinded him to reality."

Salmond added: "May presents the people of Scotland with a choice of two directions. A continuation down the route of wasting billions on a Trident replacement and ignoring international commitments to rid the world of nuclear weapons, or choosing to take the path of peace, prosperity and jobs.

Ministers say the long lead time in developing and building the replacement submarines means a decision needs to be taken soon on replacing Trident.