British Prime Minister Mr Tony Blair set himself on a collision course with the BBC tonight by warning the corporation its allegation that the dossier on Iraq's weapons had been "sexed up" was "about as serious an attack on my integrity as there could possibly be".
The Prime Minister's hardline stance came as BBC chiefs indicated they would also be unrepentant when the Foreign Affairs committee published its report on Monday into whether the Government exaggerated the case for war.
According to reports, Downing Street is to demand a full retraction of the Radio 4 Today programme story which said intelligence officials were unhappy that a claim about Saddam Hussein's readiness to strike within 45 minutes had been inserted by No 10.
In evidence to the committee and in several letters to the BBC, Mr Blair's director of communications, Alastair Campbell, has vociferously denied the information had been inserted by Downing Street.
In an interview the Prime Minister said: "The idea that I or anyone else in my position frankly would start altering intelligence evidence or saying to the intelligence services I am going to insert this, is absurd.
"There couldn't be a more serious charge, that I ordered our troops into conflict on the basis of intelligence evidence that I falsified.
"You could not make a more serious charge against a Prime Minister. The charge happens to be wrong. I think everyone now accepts that that charge is wrong."
He added: "I am astonished if they are still saying it is accurate, on what basis are they saying that?
"Whether they had a source or not, only they know. The issue surely is this, that if people make a claim and it turns out to be wrong, they should accept it is wrong."
The BBC tonight refused to back down. According to one report, Greg Dyke, a former Labour donor, is to tell BBC governors when he meets them for a briefing tomorrow evening they were facing a "Do or die" battle with the Government.
The corporation's head of news, Richard Sambrook, said the BBC stood by its story and the reporter at the centre of the storm, Andrew Gilligan.