FORMER Downing Street communications chief Alastair Campbell accused the BBC’s Andrew Marr of bias over the Iraq war last night after breaking down while being quizzed on live TV.

Mr Campbell said the interviewer had been pursuing an “agenda” in pressing him over whether Tony Blair had misled the House of Commons in the run-up to the 2003 invasion.

The ex-spin doctor was appearing on the BBC1’s Andrew Marr Show yesterday to promote his new novel, Maya, but the atmosphere deteriorated quickly when Mr Marr described the book as his “new work of fiction”.

This was taken by Mr Campbell as a barbed reference to the dossier he helped assemble on Saddam Hussein’s weapons of mass destruction.

An extraordinary exchange began after the presenter turned to the issue of whether Mr Blair had effectively lied when he told MPs it was “beyond doubt” Iraq had weapons of mass destruction.

“If beyond doubt is not established in the intelligence when this inquiry looks at the intelligence, does it then follow, yes or no, the Prime Minister misled Parliament?” Mr Marr asked.

Mr Campbell replied: “The Prime Minister did not mislead Parliament.”

But instead of continuing he then paused and appeared to be struggling for breath.

“Yes, because I said ... forgive me for this, I’ve ...”

Mr Marr told him: “People say you can’t answer this question.”

Mr Campbell again gave a reply interrupted by several pauses, saying: “I’ve been through a lot of this Andrew.

And I’ve been through a lot of that inquiry ... and, er ... Tony Blair, I think is a totally honourable man.”

Mr Campbell hit out at the “constant vilification” he had received along with Mr Blair over the conflict and the dossier of intelligence.

The claim by a BBC reporter that the dossier had been “sexed up” eventually led to the Hutton Inquiry and the resignation of the corporation’s director general, Greg Dyke.

Mr Campbell said: “You compared the novel to the dossier, that it was all fiction and all the rest of it.

“It’s not.”

He added: “I’m sorry if I get upset about this but I was there with Tony. I know how that decision weighed on him, I know the care that we took.”

Appearing on Sky News’ Sunday Live programme later, Mr Campbell explained his performance by saying: “I guess one of the reasons I did get quite upset with Andrew this morning, I feel sometimes we are treated in this media bubble like somehow you are devoid of humanity – you don’t really have feelings, you don’t really care about things.

“I know how much I care about it, I know how much Tony Blair cares about it.”