Allies of Alastair Campbell, the government's powerful director of communications and a key Blair aide, piled on pressure for the public broadcaster to apologise, accusing it of "unethical journalism" and lies.

BBC journalist-turned government minister Ben Bradshaw claimed the BBC broke its own guidelines.

"There are quite clear BBC guidelines that you should not rely on a single anonymous source," Bradshaw told BBC radio's flagship Today programme.

No attempt was made to test the truth of "the most serious accusation I can ever remember being levelled at any government", he said.

The argument centers on a BBC report in late May, in which an unidentified source said that Blair's inner circle last year "sexed up" a dossier on Iraq's weapons of mass destruction to hype up the case for war on Baghdad.

London and Washington used Iraq's alleged weapons programme as a main justification for launching a war against Saddam Hussein's regime in Iraq in March.

When John Humphreys, a star presenter for the Today programme, Saturday told Bradshaw the defence ministry had been told of the contentious BBC story the day before it was broadcast, that comment became a new bone of contention.

"This is just another example of the BBC desperately trying to defend the indefensible -- namely poor and unethical journalism," Bradshaw said.

Defence Secretary Geoff Hoon then stepped into the row, saying in a statement: "I strongly support the request to the BBC to correct this morning's misleading comments. They are simply not true."

But BBC news director Richard Sambrook mounted a robust defence of the corporation's reports.

"In terms of Ben Bradshaw today, again, he has misrepresented our journalism and the way we conducted it," Sambrook said.

At the heart of the swirling accusations and counter-allegations is a one-sentence claim in the government's September dossier, which was compiled by intelligence services.

That sentence read: "Intelligence indicates that the Iraqi military are able to deploy chemical or biological weapons within 45 minutes of an order to do so."

On May 29, BBC radio's Today programme quoted an unidentified source as suggesting that the line was inserted under pressure from the prime minister's office.

On Saturday, in a further twist to the row, Today defence correspondent Andrew Gilligan, who originally reported the allegation about the September dossier, threatened legal action.

He accused Phil Woolas, Deputy House of Commons Leader for the ruling Labour party, of trying to "blacken my character" in remarks made earlier this week.

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