The changes were argued for by Downing Street, and helped Blair rebut the principal charge that he had shown bad faith in arguing that Iraq's weapons of mass destruction (WMDs) made war necessary, the Sunday Telegraph said.

The report, issued on Wednesday by an inquiry team headed by former top civil servant Lord Butler, damned as unreliable most of the pre-war intelligence on WMDs but cleared Blair of deliberate distortion.

The newspaper cited an unnamed member of Butler's five-strong inquiry team as saying Downing Street secured changes to a passage in the report dealing with a parliamentary statement on Iraq's WMDs made by the prime minister in September 2002.

The alterations watered down the contrast between the seemingly compelling case for war made to lawmakers by Blair and the thinness of the intelligence he actually had at his disposal, the Telegraph said.

It happened during an agreed process whereby individuals facing criticism in the report were allowed to see sections of the draft relating to this with a view to giving a response.

The passage in question refers to a British government dossier on Iraq's weapons which reached conclusions at, the inquiry team said, "the outer limits" of what the intelligence allowed.

Blair's parliamentary address "may have reinforced this impression", the Butler report concluded in its final version.

However, according to the Sunday Telegraph, the original draft gave the opinion that Blair had personally masterminded this misleading impression, calling into question his good faith.

Despite being cleared of deliberate deception, Blair -- who argued the case for backing the US-led war almost exclusively on the basis of the threat posed by Iraq's WMDs -- was criticised in the report.

He was by no means in the clear, a member of the inquiry team was quoted as telling the Sunday Telegraph.

"The whole thing points straight to the man in charge ... absolutely to where responsibility belongs, which is the prime minister, which is what we could not say."

A series of reports have said that Butler, who headed Britain's civil service for a decade before his retirement in 2001, had felt it was not his place to produce a report so damning it could make Blair's position untenable.