When it comes to documentary programs, Panorama from the BBC is one of my favorites. Second after that is the Channel 4 Dispatches program.
This documentary is a must watch.
It shows how the Bush and Blair administration used questionable evidence which had been rejected by other intelligence agencies (namely France and Germany) to justify the invasion of Iraq. Evidence which understandably proved to be wrong.
It also shows how assessments were manipulated by them and by elements within their respective intelligence agencies.
A must watch.