Rodric Braithwaite, who was foreign affairs adviser to former prime minister John Major, told The Financial Times newspaper that a judicial inquiry should be launched to address the continued scepticism about the government's justification for going to war.

If within eight months or so it was shown that the case for war had been based on a non-existent threat it would "leave the government looking very tattered," said Braithwaite, a former head of parliament's Joint Intelligence Committee.

The defence ministry said Tuesday that one of its officials had come forward as the possible source of BBC claims that a dossier on Iraqi weapons had been "sexed up" on the orders of Downing Street.

However neither the defence ministry nor the BBC could confirm whether the official concerned -- who was not named -- was actually the source for BBC journalist Andrew Gilligan's story.

The disclosure came the day after parliament's foreign affairs committee produced a much-awaited report after examining the two dossiers published by the government in the run-up to war.

One, published in September 2002, included a headline-grabbing claim that Iraq could deploy chemical or biological weapons in 45 minutes.

The committee also probed the story broadcast by the BBC in late May that quoted an intelligence source as saying the government's September 2002 dossier was "sexed up" with the 45-minute claim despite doubts about its veracity among intelligence chiefs.

The BBC assertion that Prime Minister Tony Blair's office beefed up information from intelligence services to persuade a sceptical public of the case for war prompted a bitter row between the public broadcaster and the Labour government.

The foreign affairs committee's report concluded that the 45-minute claim "did not warrant the prominence given to it in the dossier, because it was based on intelligence from a single, uncorroborated source".

The defence ministry said Tuesday that the unnamed official had met Gilligan a week before he broadcast his original report.

But the official denied laying the responsibility at the door of Blair's communications chief Alastair Campbell who, Gilligan said, had been blamed by his source for the story.

There was uncertainty in the defence ministry and the BBC over whether the official concerned -- who was not named -- was actually Gilligan's source.

The BBC reported that Defence Secretary Geoff Hoon had offered to disclose the identity of the official to the corporation.

However, it was rejected by Gavyn Davies, chairman of the BBC Board of Governors, who said it was an attempt to force it to reveal its sources which would break a "cardinal" journalistic principle.

Nevertheless, Hoon strongly indicated that he thought the official probably was the source for the story.

A defence ministry statement said that the official in question was more junior and less involved in the dossier than the BBC had suggested when it attributed its story.

Meanwhile the BBC cast doubt on whether the official was actually Gilligan's source, saying that the description of the man given by the MoD did not match the source "in some important ways".

In a statement, the BBC said it stood by Gilligan's reporting of his source.

Britain's opposition parties said Tuesday that the latest developments only strengthened the case for a full judicial inquiry into the whole affair.

Meanwhile Downing Street -- which has repeatedly demanded the BBC apologise for Gilligan's story and has strongly denied it -- was saying nothing about the disclosures.

WAR.WIRE