The lies of two Iraqi spies were central to the claim - at the heart of the UK and US decision to go to war in Iraq - that Saddam Hussein had weapons of mass destruction. But even before the fighting started, intelligence from highly-placed sources was available suggesting he did not, Panorama has learned.
Six months before the invasion, the then Prime Minister Tony Blair warned the country about the threat posed by Saddam Hussein's weapons of mass destruction (WMD).
"The programme is not shut down," he said. "It is up and running now." Mr Blair used the intelligence on WMD to justify the war.
That same day, 24 September 2002, the government published its controversial dossier on the former Iraqi leader's WMD.
The BBC has learned that two key pieces of intelligence, which could have prevented the Iraq war, were either dismissed or used selectively
Designed for public consumption, it had a personal foreword by Mr Blair, who assured readers Saddam Hussein had continued to produce WMD "beyond doubt".
But, while it was never mentioned in the dossier, there was doubt. The original intelligence from MI6 and other agencies, on which the dossier was based, was clearly qualified.
The intelligence was, as the Joint Intelligence Committee noted in its original assessments, "sporadic and patchy" and "remains limited".
The exclusion of these qualifications gave the dossier a certainty that was never warranted.
Much of the key intelligence used by Downing Street and the White House was based on fabrication, wishful thinking and lies. http://www.bbc.co.uk/news/uk-21786506