"I would not have done Iraq if I had not thought it was right" he just said. Nobody doubts that. I think Hitler could have honestly said the same too. There is nothing more dangerous than a sociopath who thinks he is right.

In an interview with The Independent, Sir Christopher Meyer, the former ambassador in Washington, said he regarded it as a “badge of honour” that he had faced criticism during the inquiry from Mr Blair, his chief of staff, Jonathan Powell, and his director of communications, Alastair Campbell. He added that turning on opposition was the “modus operandi” of the Blair administration.

All three attacked Sir Christopher during their hearings after he had suggested Mr Blair may have committed troops to an invasion without gaining anything for Britain in return. Sir Christopher said that Mr Blair and President Bush had been alone for long stretches during an April 2002 meeting in Crawford, Texas, and that policy appeared to change after it.

“I said that to this day, I do not know what degree of convergence was, so to say, signed in blood at the Crawford ranch,” he said. “Powell, Campbell and Blair all made an argument as if I had asserted that I knew what had happened and I had been there.”

He said that the tactic was a hallmark of how No 10 operated under Mr Blair. “You turn on dissent, you distort the argument, you claim the other person has said something they never said, and then you seek to discredit it. It’s not only me that has had some of this. It is their modus operandi. Smear and smokescreen.”