Big Five nuclear powers braced for move to ban bomb: Moves to outlaw nuclear weapons world-wide may force permanent members of the UN body to reconsider their entry qualifications, writes Christopher Bellamy, Defence Correspondent

INTERNATIONAL law may soon transform the attitudes to nuclear weapons of the five declared nuclear powers - the five permanent members of the UN Security Council. That is why some of them are strenuously opposing moves to obtain legal advice on the issue.

Three of those members, the United States, Britain and France, are extremely sensitive about the legality of nuclear weapons. Britain and France, in particular, owe their precarious position as permanent members to their past status as great powers and to their possession of nuclear arms.

A request by the UN General assembly to the International Court of Justice (ICJ) - the 'World Court' - to advise if the threat or use of nuclear weapons is in any circumstances permitted under international law, Resolution L25, has been dropped. But another, asking if use of nuclear weapons would be a breach of international law, including the constitution of the World Health Organisation (WHO), is still being considered.

Although only confined to the health and environmental aspects, the question is causing deep unease. The US State Department has reportedly set aside dollars 800,000 ( pounds 530,000) to challenge the submission of the question to the ICJ. From 17 to 26 January, the executive board of the WHO meets to discuss its agenda for the 1994 World Health Assembly session in May. The US State Department is working 'flat-out' on a counter-resolution, saying the question lies outside the WHO's competence.

Although a straightforward challenge to the legality of nuclear arms has therefore failed, an indirect one, via their long- term health and environmental effects, could succeed. Chemical and biological weapons are already banned by international conventions. The declared nuclear powers have a vested interest in banning these weapons, which are easier for less-developed countries to make, while preserving a near-monopoly on nuclear weapons (Israel excepted), even though nuclear weapons are, potentially, more destructive. Making them illegal could have profound implications: it would give the nuclear Non-Proliferation Treaty (NPT), up for renewal in 1995, a legal basis - which it lacks at the moment.

Existing conventions ban weapons which release poisonous gases, affect neutral states, cause widespread, severe and long-term environmental damage. The prevalent view is that in some circumstances it is acceptable to blast, burn or slice people to death, while it is never acceptable to poison them, irradiate them or infect them with deadly microbes.

But nuclear weapons do have some characteristics that have led to chemical and biological weapons being outlawed - long-term and indiscriminate effects. Such effects are the target of a fundamental challenge to the privileged and increasingly anomalous position of nuclear weapons.

Suggestions that big nuclear weapons could be made illegal while small ones should be allowed have run up against the awkward fact that in big weapons the effects of blast and heat predominate, whereas below about 10 kilotons radiation effects predominate. So small nuclear weapons are less acceptable to conventional military morality than big ones.

The British government's attitude to resolutions on the legality of nuclear weapons has been robust. Asked about the fate of L25, the Minister of State at the Foreign Office, David Heathcoat-Amory, said on 24 November: 'The resolution was, in the end, not put to a vote. We believe anyway that the use of nuclear weapons would have to be judged as lawful or not in the light of the particular circumstances in which they were used and that therefore it would be wrong to burden the International Court of Justice with this hypothetical question.'

Robert Green, a former navy commander and nuclear- bomber pilot turned anti-

nuclear campaigner, has become involved in the World Court Project, as it is known. He believes it is far from a hypothetical question; such a technicality - an ICJ opinion that nuclear weapons would violate the WHO constitution - could completely upset the nuclear status quo and bring about a disarmament race which Britain could lead. If it seized on this opportunity to renounce its nuclear weapons - the first state to do so - it would gain great international prestige, making a virtue out of a new necessity.

An ICJ opinion is not mandatory, but it could cause enormous problems for anyone in charge of nuclear weapons. The Manual of Military Law says: 'If a person . . . receives an order to do some act that is manifestly illegal, he is bound under a legal duty to refuse to carry out that order'. Firing a Trident missile would be, unquestionably, illegal.

Mr Green believes an ICJ opinion could act as a catalyst, either isolating Britain further from changing world opinion or, if used cleverly, be open to exploitation. If the World Court were to deliver an opinion on the illegality of nuclear weapons before the NPT comes up for renewal in 1995, it could have a profound effect on disarmament.

Its opinion could reflect, and stimulate, a change in the mindset of governments. The time might be right. It is increasingly difficult for Britain to maintain with any sincerity that its deterrent is 'independent'. When the last of the WE-177 free-fall bombs becomes unusable, around 2006, it will be hard to see how Britain could use any nuclear weapon except as an arm of the US.

There is increasing concern about the disposal of nuclear material, and a comprehensive test-ban treaty is also on the cards. The technology of modelling the likely performance of nuclear warheads has, according to defence sources, been developed to the stage where it is no longer necessary to test warheads to keep arsenals in working condition. But it would presumably be impossible to develop new nuclear weapons without some testing. Britain, having relied on US facilities in the Nevada desert, has more of a problem than other nuclear powers.

Britain and France are nervous about their permanent membership of the Security Council. If nuclear weapons are to be the sole qualification, then why not admit Israel? If economic and political muscle are the qualification, then Germany and Japan have strong cases.

Or perhaps participation in UN peace-keeping operations around the world should carry weight - an area where Britain and France can claim to have done a certain amount. Whatever the future holds, clinging to nuclear weapons as an entry-ticket to permanent Security Council membership is looking increasingly difficult.

Should the World Court rule that nuclear weapons are illegal, many people who until recently supported the retention of nuclear weaponry might favour dismantling Britain's nuclear arsenal.