The British House of Commons has backed a government motion that Britain should use all means necessary to disarm Iraq.
Tony Blair's government won the backing of 412 MPs, with 149 voting against the government.
A rebel amendment opposing war with Iraq was defeated by 396 votes to 217.
Earlier today, the Conservative party lost three front-bench spokespeople as a consequence of the party's support of the Government on Iraq.
Leader Iain Duncan Smith suffered three resignations from his front bench: shadow environment minister Jonathan Sayeed, home affairs minister Humfrey Malins, and health minister John Baron.
A debate on the motion to disarm Iraq began in the House of Commons at 12.30pm this afternoon.
Mr Blair told MPs that the outcome of the current crisis would determine the pattern of international politics for the next generation.
Iain Duncan Smith said the Conservative Party was backing the Government on this issue.
Moving the rebel amendment, foreign Labour defence minister Peter Kilfoyle pointed out 'the idiocy of fighting the wrong war in the wrong place at the wrong time against the wrong enemy.'
Liberal Democrat leader Charles Kennedy opposed the war, but called for unity once the vote has been taken.
Three ministers now casualties of division
Three ministers have now resigned from Tony Blair's government in protest at his stance on Iraq.
This morning the junior Health Minister, Lord Hunt, and a Home Office Minister, John Denham, announced their resignations from government.
Their announcements follow yesterday's resignation from cabinet of Robin Cook.
Anne Campbell, a parliamentary aide to the Trade and Industry Secretary, Patricia Hewitt, has also resigned her position.
However International Development Secretary, Clare Short, has announced that she will not be resigning from cabinet.
Ms Short had said that she would resign if Britain went to war without a UN mandate.
Standing ovation for Robin Cook
Last night Robin Cook received a standing ovation in the House of Commons, while the Foreign Secretary Jack Straw was jeered by backbench Labour MPs when he said the diplomacy was now at an end.
MPs listened in silence to an impressive parliamentary performance as Mr Cook told them he could not support sending British troops to war without broader international support.
Welsh Assembly protest
Anti-war campaigners today forced their way into the Welsh Assembly's debating chamber to protest against conflict in Iraq.
Five protesters leapt over the barriers and into the chamber shouting for a debate on war.
They were bundled out by security guards and police and proceedings were put on hold for 10 minutes.
It is the second time such action has been taken: in October, five protesters tried to tie themselves to the presiding officer's desk.
Opera House protest
Authorities in the Australian state of New South Wales have promised to tighten security at the Sydney Opera House after activists painted an anti-war slogan on the famous landmark.
The two men who managed to scale the largest sail of the opera house daubed the words 'No War' in red paint on the top of the building. They were arrested afterwards.
Reacting to the breach, NSW Premier Bob Carr said that security was obviously not tight enough at the Sydney Harbour site, and he has requested a report on the incident.
