Vital intelligence used to justify the invasion of Iraq 10 years ago was based on "fabrication" and "wishful thinking", a new documentary claims.
A BBC Panorama investigation, broadcast to mark the 10th anniversary of the start of the Iraq War, suggests that US and UK security services relied on several pieces of questionable information, while dismissing others that were contradictory.
The war, which started on March 20, 2003, lasted over six years, claimed the lives of 179 UK personnel, more than 100,000 Iraqis, and and cost more than £9 billion.
Britain ended combat operations in 2009 but a decade on the war remains unfinished business, with ongoing questions about the legality of the invasion, and the conduct of British troops.
Panorama - The Spies Who Fooled The World - documents the chain of secret information that contributed to the decision to invade, including new testimonies from intelligence sources.
It tells how claims from a few sources that Iraq was manufacturing Weapons of Mass Destruction (WMD) spiralled into apparently sound intelligence used to justify the war.
The programme alleges that certain intelligence was relied on out of wishful thinking, with one source telling the programme the Iraq War was borne out of "choice" rather than "necessity".
In his first TV interview on the subject August Hanning, former head of German Intelligence, said Iraqi spy Rafed Al Janabi - codenamed Curveball - told German secret services he had witnessed the manufacture of chemical and biological weapons, including mobile facilities to produce them.
The information was passed by the Germans to American and British intelligence, along with concerns about its reliability, he said.
Former CIA Europe Division chief Tyler Drumheller also claimed he passed warnings about Curveball's claims up the chain of command, while Mr Hanning said he also sent a personal cable to then CIA director George Tenet. Mr Tenet denies receiving the warnings, the programme says.