The report, aired in late May on BBC radio, raised questions as to the way Prime Minister Tony Blair and his staff used intelligence in the run-up to the Iraq war.

"I believe I am not the main source," said David Kelly, a former weapons inspector, who was grilled before the House of Commons' foreign affairs committee.

He added that, from the conversation he had with Andrew Gilligan, a BBC defence specialist who filed the report, "I don't see how he could make the statements he was making from the comments that I made".

The BBC has refused to confirm whether Kelly was the "intelligence official" who was the source of the May 29 report, aired on its flagship domestic current affairs show Today.

The official claimed that a September 2002 dossier on Iraq and weapons of mass destruction -- produced by British intelligence agencies -- had been "transformed" by Downing Street a week before its release.

He said the "classic example" of tampering was an assertion, apparently from a single source, that Iraq could deploy chemical or biological weapons in just 45 minutes.

Blair strongly denies that intelligence was manipulated to beef up the case for war, while his media strategist Alastair Campbell triggered a row with the BBC by demanding an apology from the public broadcaster.

The prime minister was visiting British troops in southern Iraq when the report was aired.

When he appeared before the committee, Gilligan -- long a thorn in Downing Street's side for his Iraq reporting -- testified that he had a number of contacts he had met to discuss Iraq's weapons.

Gilligan had described his contact for the May 29 story as a "source of longstanding and I described him in the broadcast as one of the senior officials in charge of drawing up the dossier".

Kelly testified Tuesday that he had met Gilligan twice in the past, and that he had contributed to the September dossier -- but on the history of inspections and Iraqi deception, not on Iraqi weapons themselves.

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