The invasion of Iraq was of "questionable legitimacy", Britain's ambassador to the United Nations at the time of the war said today.
Sir Jeremy Greenstock told the official inquiry into the war that although he believed the military action was legal under international law, it did not have majority backing in the UN.
"I regard our participation in the military action in Iraq in March 2003 as legal but of questionable legitimacy in that it did not have the democratically observable backing of the great majority of member states, or even perhaps of the majority of people inside the UK," he said.
Sir Jeremy said he warned the Foreign Office that he was prepared to resign as ambassador to the UN in New York unless there was at least one new Security Council resolution justifying military action.
He said that he did not believe that Britain and the United States could simply say that Iraq was in breach of old resolutions dating back to the 1991 Gulf War requiring Saddam Hussein to give up his weapons of mass destruction.
"I regarded it as necessary politically and legally to have a new resolution - or at least one new resolution. There had to be a new declaration by the Security Council that Iraq was in material breach," he said.
"Because there were different views in Washington as to what they were trying to do with this draft resolution, I wanted to make it clear that if this was just a Potemkin (artificial) exercise in going to the United Nations, I didn't want to be a part of it.
"Therefore, I said I might not be able to continue as ambassador in New York if there was no further updated basis for Iraq as being in material breach."
In November 2002 the Security Council did pass resolution 1441, which provided for the return to Iraq of UN weapons inspectors and was subsequently used by Britain and the US as justification for the invasion.
Sir Jeremy explained his reasons for warning that he might be forced to resign if resolution 1441 was not passed.
At this time there were "noises off" from senior figures in the Bush administration which damaged British attempts to build international agreement on how to deal with Iraq, he said.
He told the inquiry: "The 'noises off' in Washington included noises about 'this is a waste of time, what we need is regime change, why are we bothering with this, we must sweep this aside and do what's going to have to be done anyway, and deal with this with the use of force'.
"London was presented with this and constantly argued back that it was necessary to get a resolution.
"I decided to say that if it happened to become UK policy to go along with abandoning the UN route and go to the use of force without a further resolution, that I would have personal difficulties about that.
"Maybe I thought that I should be clear about that. Maybe I thought that that was a stiffener for London on what I thought should happen.
"But I thought it was a clarifying thing to say that there were limits in what I as a permanent representative could do in New York in terms of what was going on."
He said he communicated his position to Sir Michael Jay, then permanent secretary at the Foreign Office, but could not confirm whether the foreign secretary or prime minister were informed.
Sir Jeremy admitted that the wording of resolution 1441 was "too clever for its own good" in order to meet the demands of different Security Council members.
The resolution was "equivocal" on the issues of what should happen if Saddam did not comply with its terms, and who should be the judge of whether this had happened.
Sir Jeremy said: "We never were active enough after the adoption of 1441 to try and clear up that ambiguity because we thought we had won the point in 1441."
Sir Jeremy said that if military action had been delayed for another six months to October 2003 it would have had greater legitimacy but the momentum in the US was "much too strong for us to counter".
"I did not feel that by March I could represent in my argument in the Security Council that the inspectors had had enough time," he said.
"I would have said it was more than a 50 per cent chance that if we had waited until October, the inspectors would not have found a satisfactory solution and that military force might well have been used at that point, the difference being the legitimacy involved in giving the inspectors greater time."
The inquiry was adjourned until Monday.
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