The bitterness of the row between the BBC and Downing Street over the story that claimed a dossier on Iraq weapons was "sexed up" is absolutely extraordinary.
Alastair Campbell's interview on Channel 4 News on Friday night, in which he accused the BBC of defending the indefensible, was unbelievable.
I have never seen anything like it.
The whole tenor of it was jaw-dropping.
There was table banging. It was very angry and passionate.
We are seeing someone at the heart of government for six years constantly attacked as the spin doctor in chief, and he has had enough.
He has exploded.
He has crossed some personal line and it is about this particular issue where he is absolutely convinced the BBC has lied in its report about the government's first dossier outlining the threat posed by Saddam Hussein.
The BBC report claimed a senior intelligence official had said that extra prominence was given in the dossier at Downing Street's request to a claim Iraq could launch weapons of mass destruction in 45 minutes.
The BBC, in response to Mr Campbell's attack, has given a statement again - the like of which I don't think we have seen by the BBC to government ever before.
The BBC is not just simply saying we stand by this story.
It is saying that all the way through the run-up to this war, which has split Britain down the middle, the government has been trying to intimidate BBC journalists.
It is an absolutely extraordinary unprecedented confrontation.
Everyone has a great deal to lose in all of this.
The initial judgements will be made by the Commons foreign affairs select committee and intelligence select committee which meets in private.
If those committees decide Alastair Campbell has indeed misused intelligence or intelligence has been misused in the process in Number 10 then he would have to resign in pretty humiliating circumstances.
I am sure he knows this and would acknowledge this.
If these committees decide there is no evidence whatsoever in what the BBC has been broadcasting then it would be very hard for the BBC not to apologise, not just on the Today programme but across a range of BBC News outlets.
That would be a major humiliation for BBC News.
It is perfectly possible Alastair Campbell might take his complaint to the Broadcasting Complaints Commission.
Head of BBC News Richard Sambrook has invited him to do so.
This row is now so big that neither side can afford to lose.