In a major embarrassment to Prime  Minister Tony Blair, an official British inquiry today  criticised the country's pre-war intelligence on Iraq's weapons of mass destruction saying it was "open to doubt" and "seriously flawed".

In its 196-page report, the panel headed by former civil servant Lord Robin Butler also criticised the Blair government's controversial dossier on Iraqi weapons, published in the run up to war, saying that it went to the "outer limits" of the available intelligence.

It said Blair's statement in the Commons may have "reinforced the impression" that there was "fuller and firmer" intelligence behind the assessments in the dossier than was actually the case.

The damning report, which contradicted Blair's key claim, said when British Government began considering military action against Iraq in March 2002, the intelligence was "insufficiently robust" to justify claims that Iraq was in breach of United Nations resolutions requiring it to disarm.

"Iraq did not have significant, if any, stocks of chemical or biological weapons in a state fit fordeployment or developed plans for using them," it said.

Hours afters the report was out, Blair told the Parliament he "accepts" the findings of the inquiry and  admitted that British intelligence on Saddam Hussein's weapons of mass destruction was "less certain, less founded than was stated at the time".

Accepting "full responsibility", Blair said, "The inquiry was thorough and comprehensive... we accept the conclusions."

"I accept full personal responsibility for the way the issue was presented and therefore for any errors made," he said.

The report also pointed out that since the conflict, key claims based on reports from agents in Iraq, including those that Iraq had produced biological agents, had had to be withdrawn because they were unreliable.

Lord Butler's team said ministers, officials and the intelligence agencies should have reassessed the information
as it became increasingly clear that UN Inspectors were not finding any WMD in the months immediately before the war.

The inquiry, however, concluded that there was no evidence of "deliberate distortion" of intelligence by politicians.

The report found no evidence that the assessments produced by the Joint Intelligence Commission in the run-up to
the conflict showed evidence of "deliberate distortion or culpable negligence".

Blair was quick to latch on the finding saying Butler found that 'no one lied'.

"No one made up the intelligence. No one inserted things into the dossier against the advice of the intelligence services," he said. But , the inquiry report said that the controversial claim in the dossier that some Iraqi weapons could be deployed within 45 minutes should not have been included.

The inquiry panel acknowledged that its report would lead to calls for the resignation of John Scarlett, the chairman of the Joint Intelligence Committee, who drew up the dossier and who has since been appointed the chief of Mi6, British qgency dealing with external intelligence.

It said that it hoped he would stay on. "We have a high regard for his abilities and his record," it said.

Lord Butler's team said ministers and officials and the intelligence agencies should have reassessed the information  as it become increasingly clear that UN Inspectors were not finding any WMD in the months immediately before the war.

The report was highly critical of intelligence-gathering in Iraq.

"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 ntelligence assessments received by minsters and officials in the periodfrom summer 2002 to the outbreak of hostilities," it said.

The report disclosed that one Mi6 "main source", whilereporting authoritatively on some issues, had simply beenpassing on what he hadheard from "within his circle" on other issues.

Reporting from a "sub source" to second Mi6 main surce, which had led to important JIC assessents on Iraqi possesson of chemical an biologial weapons, "must be open to doubt" the report said.

Reports from a third Mi6 main source had been withdrawn as "unreliable" while reports from two further main Mi6  sources which were regarded as reliable had been notably "less worrying" about Iraq's chemical and biological capabilities.

One of the reasons that so many reports turned out to be "unreliable or questionable" could have been the length of the reporting chains.

"We detected a tendency for assessments to be coloured by over-reaction to previous errors. As a result, there was a risk of over-cautious -- or worse-case estimates, shorn of their caveats, becoming the 'prevailing wisdom', the report said.

It said that the inquiry had shown the "vital importance" of effective scrutiny of human intelligence sources in the preparation of JIC assessments and in giving high quality advice to ministers.