LONDON - An official inquiry into the quality of British intelligence on Iraqi weapons of mass destruction said Wednesday that some sources were "seriously flawed" or "unreliable" but found no evidence of "deliberate distortion or culpable negligence."

The report contradicted a central claim made by Prime Minister Tony Blair and found that, before the outbreak of war in March 2003, Iraq "did not have significant, if any, stocks of chemical or biological weapons in a state fit for deployment or developed plans for using them."

Blair had said before the war that Saddam Hussein could have weapons of mass destruction ready for use within 45 minutes.

Lord Butler findings said a key report prepared by Blair's government on the threat posed by Saddam Hussein pushed the government case to the limits of available intelligence.

He found that vital qualifying details on the limits of the available intelligence were left out of the September 2002 report.

Lord Butler was highly critical of British intelligence-gathering in Iraq and his findings closely mirrored those of the U.S. Senate Intelligence Committee which has recently found American intelligence also highly flawed.

"Validation of human intelligence sources after the war has thrown doubt on a high proportion of those sources and of their reports, and hence on the quality of the intelligence assessments received by ministers and officials in the period from summer 2002 to the outbreak of hostilities," it said.

The report acknowledged that its conclusions would probably lead to calls for the resignation of John Scarlett, who as chairman of the Joint Intelligence Committee drew up the government intelligence report. He has since been appointed the chief of MI6, Britain's secret intelligence service.

The Butler report, however, said it hoped Scarlett would stay on. "We have a high regard for his abilities and his record," it said.

Butler told a news conference that failures were "collective" and Scarlett should not bear sole responsibility.

The informality of the procedures within Blair's government for forming policies on the risks posed by Iraq "reduced the scope for informed collective political judgment," the report found.