Tony Blair arriving at the Royal Courts of Justice

Britain's prime minister, Tony Blair, told a judicial inquiry under stiff questioning that he had staked his political future on the accuracy of a controversial government report documenting Iraq's weapons capability.

Tony Blair told the inquiry that he had no reason to doubt the intelligence behind the claim that Iraqi leader Saddam Hussein's regime could launch chemical and biological weapons on 45 minutes' notice.

It is that point that has become the primary focus of the September government report that has proven to be the most contentious as Mr. Blair's government made its case for war in Iraq.

Mr. Blair said that if there had been any truth to a British Broadcasting Corporation report claiming that his government had exaggerated information about Iraqi weapons, he would have had to resign as prime minister.

Mr. Blair was testifying in the investigation into the death of a top British weapons expert, Dr. David Kelly, who apparently committed suicide days after he was identified as the source of the BBC report.

On Wednesday, the prime minister's chief intelligence adviser testified that the claim about Iraq's ability to quick-launch weapons of mass destruction had come from a single source quoting a senior Iraqi military official, which he hinted was second-hand information.

The 45 minute line came after calls by a senior Blair adviser to harden up the language of the weapons document.

On the issue of naming Dr. Kelly as the source of the BBC story, Tony Blair said he took full responsibility. Although he said the matter was handled initially by the Defense Ministry press office, he was kept in close consultation.

Demonstrators in front of court building

Mr. Blair also rejected suggestions that the document was the trigger for his decision to go to war. "The strategy was not to use the dossier as the immediate reason for going to conflict, but as the reason why we had to return to the issue of Saddam's weapons of mass destruction," he said.

Mr. Blair's demeanor was calm and professional during questioning, but it is unlikely that he will gain much of a political bounce from his appearance. Months after the major fighting in Iraq ended, no weapons of mass destruction have been found and the prime minister is facing the most severe criticism he has run into in his six years in power.

Mr. Blair, only the second prime minister to appear in public before a judicial inquiry, was greeted by about 200 jeering demonstrators outside of the Royal Courts of Justice in London. His credibility remains at stake, and if no evidence of weapons of mass destruction is produced, the British leader's reason for pushing the nation into a distant war could come in for even more criticism.