Former BBC director general Greg Dyke has accused British Prime Minister Tony Blair of trying to force the corporation to change its tone of coverage of the Iraq war and the issue of weapons of mass destruction.

In his book Inside Story, serialised in The Observer, Dyke said Blair, in a letter to him and the then BBC chairman Gavyn Davies tried to bully the Corporation.

"It seems to me there has been a real breakdown of the separation of news and comment," Blair wrote in the letter dated March 19, 2003 a week before the war on Iraq began.

He claimed that Blair later regretted sending the letter, but had been persuaded to do so by the then communications director Alastair Campbell.

He said Campbell had become "obsessed" with trying to "beat" the BBC, was out of control, vindictive and eventually had to be removed by the PM.

Dyke wrote: "Blair was either incompetent and took Britain to war on a misunderstanding, or he lied when he told the House of Commons that he didn't know what the 45-minute claim meant.

"We were all duped. History will not be on Blair's side. It will show that the whole saga is a great political scandal."

The book also claimed that Blair broke a promise to Davies that he would not demand the resignations of the former chairman or Dyke following publication of the Hutton report.

The Hutton inquiry was set up after the death of David Kelly, the government scientist linked to claims on Radio 4's Today programme that Downing Street had 'sexed up' intelligence to make a stronger case for war.

Both Davies and Dyke left the BBC within 36 hours of the report's appearance, after Campbell accused the corporation of lying in an officially sanctioned statement.

The book revealed fresh doubts at the very top of the intelligence services about claims that then Iraq president Saddam Hussein was an international threat.

Dyke said that John Scarlett, former head of the Joint Intelligence Committee, who was promoted by Blair to head of MI6, had professed private doubts to a BBC journalist about the case for war.

In particular, he was concerned by claims that Hussein could launch a chemical or biological weapons attack within 45 minutes of an order to do so.

Dyke revealed when the BBC did finally apologise after he quit, they first checked the statement with 10, Downing Street.

"I had no idea I would be fired by a board of governors behaving like frightened rabbits caught in car headlights," Dyke said.

"The new BBC chairman, Michael Grade, needs better, more knowledgeable, governors to support him. There is no greater betrayal of BBC principles than to fold under political pressure, particularly from the government of the day," he said.