The head of the United Nations weapons inspectors in the run-up to the Iraq war, Hans Blix, last night undercut one of the main grounds offered by the attorney general, Lord Goldsmith, in his legal advice to Tony Blair.
Lord Goldsmith said there would have to be evidence that Iraq was not complying with the inspectors.
But Mr Blix, who has since retired to Sweden, said his inspectors found no compelling evidence that Iraq had a hidden arsenal or was blocking the work of the inspectors. He said there had been only small infractions by Iraq.
"We did express ourselves in dry terms but there was no mistake about the content," he said. "One cannot say there was compelling evidence. Iraq was guilty only of small infractions. The government should have re-evaluated its assessment in the light of what the inspectors found.
"We reported consistently that we found no weapons of mass destruction and I carried out inspections at sites given to us by US and British intelligence and not found anything."
In a key passage in the legal advice written by Lord Goldsmith on March 7 2003, the attorney general said that UN resolution 1441 could only be sustainable as a justification for war "if there are strong factual grounds for concluding that Iraq has failed to take the final opportunity. In other words, we would need to be able to demonstrate hard evidence of non-compliance and non-cooperation."
He said the views of UNMOVIC, the UN inspectorate body, and the International Atomic Energy Agency, the UN nuclear watchdog, will be "highly significant" and "you will need to consider very carefully whether the evidence of non-cooperation and non-compliance by Iraq is sufficiently compelling".
Mr Blix and his team returned to Iraq in December 2002 after a four-year absence and remained until the week before war began in March 2003. More than 200 inspectors crisscrossed Iraq, checking out possible sites for the production or stockpiling of weapons of mass destruction: chemical, biological or nuclear.
Mr Blix's first monthly report to the UN security council in January was mainly negative about the Iraqi government, complaining about lack of cooperation. A month later he adopted a more neutral stance, pointing out some infringements but finding no significant stockpiles.
On March 7, the day Lord Goldsmith drew up his report, Mr Blix gave his final report and this was the most favorable yet from Iraq's point of view.
Asked if this final report amounted to the compelling evidence that Lord Goldsmith considered crucial, Mr Blix said: "One cannot say so. There were infractions, you can say. In March, they (the Iraqis) cooperated like hell. They were pro-active. In December and January, no. That is why I gave a critical account on January 27. In February, it was more balanced."
On March 7, Mr Blix pleaded for more time to complete his mission and reported that lethal weapons such as Samoud 2 missiles were being destroyed.
Mr Blix said last night: "The things found were all small things. We found dozens of munitions for chemical weapons. They were empty and in a site declared. In relation to Samoud that went beyond 150 kilometers, they (the US and Britain) said it was beyond the permitted limit but I did not feel particularly indignant about that."
On the same day, the head of the IAEA, Mohamed ElBaradei, reported that there was no evidence that Saddam Hussein had any nuclear weapons or was in the process of acquiring them. Mr Blix said: "By then, Mohamed ElBaradei revealed that Niger was not authentic." British intelligence falsely claimed Iraq had been trying to acquire uranium from Niger.
Mr Blix said Mr ElBaradei had also challenged US claims that aluminum tubes found were for WMD purposes. Mr Blix himself also expressed skepticism to the US secretary of state, Colin Powell, about alleged evidence of WMD.
The Iraq Survey Group, set up by the US to search for WMD, found none.
In Britain, inquiries into the route to war have been held by MPs, Lord Hutton and Lord Butler. The intelligence service was criticized for not re-evaluating its assessments in the light of Mr Blix's reports.
© Guardian Newspapers Limited 2005