MI6, desperate to find evidence which would prove that Saddam Hussein had weapons of mass destruction, thought they had at last struck gold – a source with “phenomenal access” to the highest echelons of the Iraqi regime, one who would be the “key to unlock” the secrets of a chemical and biological arsenal.

The prized undercover “asset” not only confirmed that the WMD programme was going full blast but that the regime was actually building more facilities. The head of MI6, Sir Richard Dearlove, was confident that the man would even produce a “CD with everything in it.” Under the circumstances the service’s reporting of a “ significant breakthrough” seemed, if anything, to be an understatement.

Doubts, however, began to creep in. One MI6 officer pointed out that the source’s description of the device and its spherical glass contents was “ remarkably similar to the fictional chemical weapons portrayed in the film The Rock”. In the film, according to the blurb which accompanied it, a FBI chemical warfare agent, played by Nicolas Cage, is sent on a mission with a British spy, Sean Connery to stop a mad general, Ed Harris, from launching chemical weapons on Alcatraz Island into San Francisco.

Chilcot report: Key points from the Iraq inquiry in 90 seconds

Nevertheless, what the Iraqi agent had to say played an important part in the conclusions of the dodgy dossier on Iraq’s WMD. Crucially, the material was not shown to the real experts on the subject, the scientific analysts of DIS ( Defence intelligence Staff) by the JIC ( Joint Intelligence Committee) who were putting the document together.

The Chilcot report points out that “ The SIS ( MI6) report should have been shown to relevant experts in the DIS who could have advised their senior managers and assessment staff. Expert officials in the DIS questioned the certainty with which some of the judgments in the dossier were expressed.”

The inquiry also noted "Sir Richard Dearlove's personal intervention, and its urgency, gave added weight to a report that had not been properly evaluated and would have coloured the perception of ministers and senior officials. The report should have been treated with caution”.

The great scoop was unraveling fast. It was noted by MI6 on 2nd February 2003 that the source had failed to provide the information expected. By 18th February, the man was being described in MI6 notes as a liar who had been misleading them for a long time. But MI6 failed to tell others involved in producing the dossier about the debacle. Reports from the Iraqi was still being issued in April, a month after the war had begun.

MI6 finally met the source in June 2003. He had only been involved in Iraq’s chemical programme, in a minor capacity, before 1991. He denied providing any of the tantalizing material attributed to him. MI6 "concluded that its source was a fabricator who had lied from the outset". In July 2003, the “ intelligence” was officially withdrawn. The Chilcot Inquiry noted "the withdrawal of the reporting was done in a very low key manner compared with the way in which the original intelligence was issued’’.

The most iconic images from the war in Iraq Show all 20 1 /20 The most iconic images from the war in Iraq The most iconic images from the war in Iraq U.S. Navy Hospital Corpsman HM1 Richard Barnett, assigned to the 1st Marine Division, holds an Iraqi child in central Iraq, March 29, 2003 Reuters The most iconic images from the war in Iraq An explosion rocks Baghdad during air strikes March 21, 2003 Reuters The most iconic images from the war in Iraq An Iraqi woman watches U.N. weapons inspectors leave Saddam airport in Baghdad March 18, 2003 Reuters The most iconic images from the war in Iraq An Iraqi girl holds her sister as she waits for her mother (R) to bring over food bought in Basra March 29, 2003 Reuters The most iconic images from the war in Iraq U.S. Marine Corp Assaultman Kirk Dalrymple watches as a statue of Iraq's President Saddam Hussein falls in central Baghdad's Firdaus Square, April 9, 2003 Reuters The most iconic images from the war in Iraq US Marines kick in a door while securing a building next to the main hospital in central Baghdad April 15, 2003 Reuters The most iconic images from the war in Iraq A soldier of U.S. Army's 4th Infantry Division (Task Force Ironhorse) searches through dense vegetation around the Diala river where Iraqi militants are hiding outside Baquba early November 13, 2003 Reuters The most iconic images from the war in Iraq An Iraqi detainee gestures toward U.S. soldiers through bars of his cell at Abu Ghraib prison outside Baghdad May 17, 2004 Reuters The most iconic images from the war in Iraq Mays, a young Iraqi Shi'ite girl, cries after a mortar shell which landed outside the family's home in a Najaf residential area injured her uncle August 18, 2004 Reuters The most iconic images from the war in Iraq U.S. Marines carry an injured colleague to a helicopter near the city of Falluja, November 10, 2004 Reuters The most iconic images from the war in Iraq An Iraqi man suspected of having explosives in his car is held after being arrested by the U.S army near Baquba, Iraq, October 15, 2005 Reuters The most iconic images from the war in Iraq A wounded Iraqi woman is helped after several bomb attacks in central Baghdad, July 27, 2006 Reuters The most iconic images from the war in Iraq A man runs down a street warning people to flee shortly after a twin car bomb attack at Shorja market in Baghdad, February 12, 2007 Reuters The most iconic images from the war in Iraq An Iraqi girl holds her hands up while U.S. and Iraqi soldiers search her family house in Baquba early June 30, 2007 Reuters The most iconic images from the war in Iraq An Iraqi woman tries to explain that she has nothing to do with illegal fuel as soldiers from the 2nd battalion, 32nd Field Artillery brigade patrol search for illegal fuel sellers in Baghdad August 6, 2007 Reuters The most iconic images from the war in Iraq U.S. President George W. Bush (L) walks in front of Humvees with Defense Secretary Robert Gates (C) and Secretary of State Condoleezza Rice following remarks to the press after nightfall at Al-Asad airbase in Anbar Province September 3, 2007 Reuters The most iconic images from the war in Iraq U.S. soldiers blindfold an Iraqi man after arresting him during a night patrol at the Zafraniya neighborhood, southeast of Baghdad September 4, 2007 Reuters The most iconic images from the war in Iraq An Iraqi baby lies in a cradle while a woman argues with U.S. soldiers of 1/8 Bravo Company searching for weapons, explosives and information about militants in the area during a foot patrol in a neighbourhood of Mosul June 26, 2008 Reuters The most iconic images from the war in Iraq Policemen cry during a funeral of their colleague a day after a bomb attack in Baghdad's Jihad district November 3, 2010 Reuters The most iconic images from the war in Iraq Staff Sgt. Keith Fidler kisses his wife Cynthia, as their son Kolin looks on, during a homecoming ceremony in New York, April 8, 2011 for the New York Army National Guard's 442nd Military Police Company's return from Iraq Reuters

The withdrawl of the “evidence” was not known by ministers giving evidence to the inquiry by Lord Hutton into the death of Dr David Kelly in 2004, but was known by them at the time of inquiry by Lord Butler in the same year.

The “ Hollywood episode” was just the most colourful of many flaws in the dossier in which there was exaggeration and omission in the intelligence. The JIC broadly produced what Tony Blair’s government wanted to hear and it remained silent when the Prime Minister even ignored what caveats there were in the dossier to make his case for war.

Sir John Chilcot said “: “ In the House of Commons on 24 September 2002, Mr Blair presented Iraq’s past, current and future capabilities as evidence of the severity of the potential threat from Iraq’s WMD”.

“ He said that, at some point in the future, that threat would become a reality. The judgments about Iraq’s capabilities in that statement, and in the dossier published the same day, were presented with a certainty that was not justified…. It is now clear that policy on Iraq was made on the basis of flawed intelligence and assessments. They were not challenged, and they should have been….”

The view of Britain’s intelligence community before the decision to produce the dossier was that “the threat from Iraq was viewed as less serious than that from other key countries of concern --- Iran, Libya and North Korea.” But this did not suit the government and Jack Straw, the then foreign secretary, played a key role in trying to make Iraq a target.

The government had commissioned an intelligence paper on the WMD threat from “rogue” states. On seeing it, on 8th March 2002, Mr Straw wanted to stress “ Good, but should not Iraq be the first and also have more text? The paper has to show why there is an exceptional threat from Iraq. It does not quite do this yet.” On 18th March, the report noted, the foreign secretary decided that a paper on Iraq should be issued without mentioning other countries of concern. However, four days later, “ Mr Straw was advised that the evidence would not convince public opinion that there was an imminent threat from Iraq. Publication was postponed”.

Tony Blair: Soldiers did not die in vain

The operation to find “evidence” that would convince the public that military action was justified was under way. The task of doing this, through a dossier, was given to John Scarlett, the chairman of the JIC.

The JIC’s starting basis was to totally ignore the possibility that Iraq may not actually have any WMDs. “ At no stage was the hypothesis that Iraq might not have chemical. Biological or nuclear weapons or programmes identified and examined by the JIC…Iraq’s statements that it had no weapons or programmes were dismissed as further evidence of a strategy of denial.”

In a foreword he wrote to the dossier, Mr Blair declared that “ assessed intelligence” had “ established beyond doubt” that Saddam Hussein had “ continued to produce chemical and biological weapons, that he continues in his efforts to develop nuclear weapons, and that he had been able to extend the range of his ballistic missile programme”.

But, the report points out : “ the assessed intelligence had not established beyond doubt that Saddam Hussein had continued to produce chemical and biological weapons … The main text of the dossier said that there had been “ recent” production. It also stated that Iraq had the means to deliver chemical and biological weapons [but] it did not say that Iraq had continued to produce weapons.” The report also points out “ the dossier made clear that, as long as sanctions remain effective, Iraq could not produce a nuclear weapon.”

The report stresses that “ the firmness of Mr Blair’s beliefs, despite the underlying uncertainties, is important in considering how the judgments in the Foreword would have been interpreted by Cabinet and in its discussions and by Parliament.