Bush led with 259 false statements, 231 about weapons of mass destruction in Iraq and 28 about Iraq’s links to al-Qaeda, the study found.

That was second only to Powell’s 244 false statements about weapons of mass destruction in Iraq and 10 about Iraq and al-Qaeda.

The centre said the study was based on a database created with public statements over the two years beginning on September 11, 2001, and information from more than 25 government reports, books, articles, speeches and interviews.

“The cumulative effect of these false statements — amplified by thousands of news stories and broadcasts — was massive, with the media coverage creating an almost impenetrable din for several critical months in the run-up to war,” the study concluded.

“Some journalists — indeed, even some entire news organisations — have since acknowledged that their coverage during those pre-war months was far too deferential and uncritical. These mea culpas notwithstanding, much of the wall-to-wall media coverage provided additional, ‘independent’ validation of the Bush administration’s false statements about Iraq,” it said.