Pressures are building up for Blair.
More than 100 of his Labour MPs threaten to oppose military action without more evidence from U.N. weapons inspectors against Iraqi President Saddam Hussein.
The public too remains unconvinced. Talking to Londoners this week, doubts were raised over sufficient proof to justify an attack, the cost of a war and the motives, with one man saying it was just about oil.
One issue is crucial. Polls indicate that if the United Nations authorises an invasion of Iraq, then 73 percent of the British public will back it. But what if the United Nations doesn't?