The war on Iraq will be condemned as illegal by a panel of eminent international lawyers at a conference being organised by the actor Corin Redgrave.
The symposium, to be held next Sunday at the Young Vic theatre in London, will also hear senior legal experts allege that the conflict has seriously weakened the authority of the United Nations and potentially threatened global security.
The panellists include Professor Philippe Sands QC, a member of Cherie Booth's Matrix chambers, Professor Christine Chinkin, professor of international law at the London School of Economics, and Jan Kavan, the president of the UN General Assembly and former Czech foreign minister.
Another prominent speaker, Professor Burns Weston, a human rights lawyer at the University of Iowa in the US, fears that other countries might use the American decision to wage war illegally to justify their own unlawful wars. He is most concerned about India and Pakistan - two nuclear powers in dispute over Kashmir. "It is a very bad precedent for other countries that might seek, in their own lack of wisdom, to emulate the United States," he said.
The event, called "Liberation or War Crime" will be chaired by the former Radio 4 Today programme presenter Sue MacGregor and is expected to attract other prominent figures, including the playwright David Hare, the Booker Prize-winning Indian writer Arundhati Roy and the former foreign secretary Robin Cook.
Prof Sands, one of 16 prominent international lawyers who earlier this year publicly warned Tony Blair that the war was illegal, said the conflict raised two major issues.
"First, did the Security Council authorise the use of force, and the answer to that is no. And [second] were we misled about the presence of weapons of mass destruction? Apparently, yes. These things are going to come back to haunt us," Prof Sands said.
Mr Redgrave, whose film roles include parts in Four Weddings and A Funeral, Enigma and In the Name of the Father, said one objective in staging and paying for the event was to investigate the damage caused by the war to international peace.
"Very early on, before the war began, it seemed that one of the main casualties of war was the whole fabric of international law and convention," he said. "It seemed to me there was a willingness, indeed a desire, on the part of America at least, to rend that fabric in a way that would almost make it irreparable."
The controversy over the legality of the war partly subsided on Thursday after the US supported an unexpectedly far-reaching resolution at the Security Council guaranteeing Iraq's independence and giving the UN a more powerful role in its reconstruction.
Although the resolution answered widespread concerns that the occupation of Iraq was also illegal - concerns shared by the Attorney General, Lord Goldsmith - British lawyers warned there were still serious worries over the legality of the coalition's conduct.
Peter Carter QC, chairman of the Bar Council's human rights committee, said coalition forces were in breach of UN Resolution 1325, which requires participants in a conflict to have particular regard to the rights of women.
Since the war, Mr Carter said, women feared more for their safety because of the frequent looting, chaos and unlawfulness. "Women must feel free to walk the streets and go about their business. It is true to say that Iraqi women during Saddam's rule experienced greater freedoms than in other Arab countries."
Prof Sands said the new UN resolution had, for the first time, cancelled all previous legal or contractual rights to Iraq's oil - giving the coalition freedom to sell the oil to whichever firm they wanted. This raised "far-reaching" questions about the rights of an occupier to control a country's natural resources.
'There was no threat. There was no resolution'
Professor Philippe Sands QC
Director of the Centre on International Courts and Tribunals, University College London
The war was contrary to international law and it was contrary to international law whether or not they find weapons of mass destruction. The illegality was based on the absence of a Security Council resolution authorising the use of force. I think that is the view of almost every independent commentator.
The claim by the Attorney General, Lord Goldsmith - that the war was legal because Saddam Hussein had failed to comply with UN resolutions dating back to Iraq's invasion of Kuwait - has received almost no support outside the UK or the United States from independent academic commentators.
Professor Robert Black QC
Professor of Scots law, Edinburgh University, and architect of the Lockerbie trial in The Hague
It's simple and straightforward. There are only two legal justifications for attacking another country: self-defence, or if the Security Council authorises you to do so. It is perfectly plain that none of the Security Council resolutions relating to Iraq authorised armed intervention. It's possible to cobble together what looks like a legal argument, but the real test of any legal argument is whether a court would accept that argument. I challenged the Attorney General to say what he thought the odds were of the International Court of Justice in The Hague accepting his argument. In my view, the odds against were greater than 10 to 1.
Professor Sean Murphy
Associate professor of law at George Washington University, Washington DC
I think there's a real question to be raised about whether the US, UK and Australian coalition properly intervened in Iraq without Security Council authorisation, and I think there are very sound reasons for saying that the intervention was not permitted. The US-UK legal justification, which is based on Security Council resolutions dating back to 1990-91, isn't credible. When you look closely at the resolutions and the practice of the Security Council, it's clear that the majority of members of the Security Council believed that further authorisation was needed in March 2003 than, in fact, existed.
Professor Vaughan Lowe
Chichele Professor of Public International Law, All Souls College, Oxford
The new resolution provides a firm legal basis for the coalition occupation of Iraq. It gives the UN a role that is prominent on paper but which, in fact, is not at all powerful on the ground. The coalition practically has a free hand in 'promoting' reform and the formation of an interim administration ... The key question is how far the coalition may proceed with economic and political restructuring in Iraq before the election of a government by the Iraqi people. The resolution does not spell that out; nor does it fix any timetable for the return of power to the Iraqi people. Nor does it stipulate how the massive reconstruction costs of the programme - and the benefits, in terms of commercial contracts - will be distributed.
Professor James Crawford
Whewell Professor of International Law, Jesus College, Cambridge
On the information available, none of the exceptions that permit the use of force applied. There was no UN Security Council authorisation, and no imminent humanitarian catastrophe, and no imminent threat of the use of force by Iraq. I think it was unlawful in the beginning, and they haven't found anything since to make one change one's mind.
The earlier Security Council resolutions were related to the occupation of Kuwait, and that situation has completely changed. It's very contrived to treat Resolution 1441 as if it authorises the use of force.
Professor Mary Kaldor
Professor of global governance, London School of Economics
Going back to the 1991 UN resolutions is the real weakness of their argument. It is an awfully long time ago, and it's as though this isn't a new war - as if it is the same war we fought in 1991. I think that it is an incredibly weak legal case. I don't think there's any way we can argue that the Iraq intervention was legitimate, and it's illegitimate for two reasons. There was no real case that the inspectors weren't dealing with the weapons of mass destruction. And, we're now seeing what a lot of people warned we would see: that this will be bad for [curbing] terrorism rather than good.