Anyone who believes Saddam Hussein possessed no weapons of mass destruction will be left "eating some of their words" when the banned arms are found, Prime Minister Tony Blair (search) predicted Wednesday.

In a feisty performance at the House of Commons (search), Blair shrugged off an opposition lawmaker's question whether he would resign if inspections failed to turn up chemical, biological or nuclear weapons -- the coalition's main argument for invading Iraq.

"Forgive me if I refuse to engage in all sorts of speculations," Blair said in response to the question from Conservative lawmaker Peter Tapsell. "But let me say to him, I am absolutely convinced and confident about the case on weapons of mass destruction (search).

"And I simply suggest to him, and others who believe somehow that this was all a myth invented by us, I would refer them first of all to the 12 years of United Nations reports detailing exactly what weapons of mass destruction were held by the then Iraqi regime."

Coalition forces in Iraq have identified some 1,000 sites they wished to search for banned weapons.

There have so far been no confirmed discoveries of weapons of mass destruction by coalition troops, and Blair's critics argue that the failure to find any banned arms proves the war in Iraq was unnecessary.

But on Wednesday, the prime minister again asserted that evidence of Iraq's illicit arms programs would be found.

"We are now in a deliberative way and in a considered way investigating the various sites and we will bring forward the analysis and the results of that investigation in due course," Blair told lawmakers. "And I think when we do so, the honorable gentleman and others will be eating some of their words."

Also Wednesday, Foreign Secretary Jack Straw said it would take time to uncover the well-hidden details of Saddam's weapons program.

"We know that for six months prior to the return of U.N. inspectors, Saddam put in place a systematic campaign of concealment. So it is hardly surprising that concrete evidence of weapons of mass destruction has yet to come to light," Straw told dignitaries at the Lord Mayor's Easter banquet in central London.

"Assembling an accurate picture of Saddam's program will take time."