Saddam Hussein has "one further final chance" to disarm peacefully, UK Prime Minister Tony Blair has warned.
In one of the most important speeches of his political career, the UK prime minister demanded Iraq's "100% compliance".
"Anything less will not do," he told a packed House of Commons.
But the government still faces a rocky ride from some MPs with 115 likely to reject Mr Blair's stance on war saying the case for military action has yet to be proven.
They are believed to include Tories Kenneth Clark, John Gummer, and Douglas Hogg as well as several prominent Labour ex-ministers.
A further 47 Liberal Democrats are also believed to be preparing to voice concern.
As he tried to win over critics to his stance on Iraq, Mr Blair said inaction would make a future war more appalling, as well as undermining the United Nations.
He said: "This is not a road to peace, but folly and weakness which will only mean that when the conflict comes, it will be more bloody, less certain and greater in its devastation."
There was no "rush to war" and Saddam had been given 12 years to disarm voluntarily, said Mr Blair.
The US and UK this week unveiled their new draft UN resolution, with a vote likely to follow within the next "two weeks or so".
Mr Blair said: "We will not put it to a vote immediately. Instead we will delay it to give Saddam one further final chance to disarm voluntarily."
The weapons inspectors would report again in March, he said.
"But this time Saddam must understand - now is the time for him to decide."
Mr Blair said he "detested" the Iraqi regime, but even now Saddam could save his government by disarming peacefully.
In a US television interview, the Iraqi president has hinted he would not agree to United Nations demands that he destroy banned missiles.
Chief UN weapons inspector Hans Blix said on Tuesday that there is no room for negotiation over the Al-Samoud missiles.
NEXT STEPS IN IRAQ CRISIS
28 Feb or soon after: Blix written report to Security Council
1 Mar: Missile destruction must start
Around 7 Mar: Inspectors oral report to Security Council
10 Mar: US-UK will force UN vote on resolution
Mr Blair predicted that Saddam would start "playing games" over the missiles.
On Wednesday, MPs will have the opportunity to debate a government motion, which tells Saddam he has his "final opportunity" to get rid of his weapons of mass destruction.
France and Germany, backed by Russia, have countered the new Anglo-American UN resolution with their own memorandum pushing for an extra four months of enhanced weapons inspections.
Mr Blair dismissed their calls, saying that without Iraqi cooperation, it was "absurd" to think inspectors could sniff out arms - however much time they had.
His stance won support from Conservative leader Iain Duncan Smith.
But Liberal Democrat leader Charles Kennedy criticised Mr Blair for his "shifting arguments" over tackling Iraq, which had left the British public "highly sceptical".
The prime minister was meeting German Foreign Minister Joschka Fischer and King Abdullah of Jordan on Tuesday as part of his diplomatic drive.
After Mr Blair's meeting with King Abdullah a joint statement was issued by Downing Street.
It said that both the UK and Jordan favour a "peaceful solution through full Iraqi disarmament" but that time was running out.
"The UK and Jordan agree that this is the final opportunity for peace in the region and we call on Iraq not to lose this opportunity," the statement said.
Mr Blair was also holding talks with General Tommy Franks, head of US central military command, who is meeting defence officials in London.
Ahead of Wednesday's debate on Iraq, a cross-party group of MPs tabled an amendment to the government's motion saying the case for military action was "as yet unproven".