THE problems created by the collapse of the Soviet empire are so huge - and so unexplored - that Britain is pressing for a summit of world leaders to grapple with them.
Prime Minister John Major hopes to chair a special meeting of the United Nations Security Council during his country's month-long presidency, which began Jan. 1.
First, Mr. Major wants top-level discussion of the threat of nuclear proliferation by members of the new Commonwealth of Independent States.
The economic crisis in the commonwealth and the likelihood of ethnic violence such as that in Georgia and Yugoslavia, are also subjects at the top of Major's agenda.
Major's officials say Russian President Boris Yeltsin has shown interest in attending a summit at which he would formally take over the UN seat previously occupied by the Soviet Union. Others invited would be President Bush, France's President Francois Mitterrand, and an unspecified Chinese leader.
Major has described the nuclear proliferation threat as "serious in the longer term." On Jan. 1 he warned of the dangers of the commonwealth's smaller republics being tempted to sell nuclear know-how and material to third-world countries.
But those dangers are only two of many factors in the aftermath of the Soviet breakup that persuade Major and his ministers that the world has entered a period of uncertainty and unpredictable crisis. The prime minister believes a meeting of world leaders under UN auspices would provide a starting point for a continuing review.
As well as focusing attention on the situation created by the Soviet breakup, the British initiative is seen as having an important domestic political dimension in a general election year.
It reflects British government fears that as the European Community (EC) becomes more unified, London's voice at the UN and in other international forums is in danger of being diminished.
Britain would prefer the UN summit to be confined to the five permanent members of the Security Council but, officials say, it might agree to a meeting of all 15 members of the Security Council, if current soundings in New York show a desire for that.
British officials said the meeting would give world leaders the chance for an early meeting with Boutros Boutros-Ghali, the new United Nations secretary-general, who is already having to address the post-Soviet crisis.
Major spoke of his worries about the nuclear capacity of the former Soviet republics in a New Year's Day radio interview. "It is obviously a long-term worry," the prime minister told the British Broadcasting Corporation. "It is not just a question of who owns the nuclear weapons but also whether some of the smaller republics might sell all or a part of their nuclear-weapons armory."
There was a risk too that nuclear scientific expertise in some of the commonwealth republics might be purchased by third-world countries, he added.
Russia, the Ukraine, Byelorussia, and Kazakhstan are known to have strategic nuclear weapons arsenals.
Last week Eduard Shevardnadze, the former Soviet foreign minister, said short-range nuclear weapons were still deployed in several other former Soviet republics.
Many in Britain harbor unspoken concerns that the Muslim republics in the commonwealth might share nuclear knowledge with other Muslim states, including adversaries of the West.
Prime Minister Major stressed that a UN summit would enable world leaders to assess the rapid decline of the former Soviet economy and the danger of increasing internal unrest.
Major has his own political reasons for taking the initiative on a UN summit, according to Labour opposition spokesmen. This is a general-election year in Britain and summit exposure for the prime minister in the next few weeks would help his electoral prospects by drawing attention away from the languishing domestic economy.
British diplomatic sources conceded that Major was attempting to underline Britain's determination to keep a firm grip on its position as one of the five permanent members of the Security Council with veto power.
Members of several EC governments have suggested that the EC, which is trying to develop its own foreign-policy profile, should have its own seat on the council. This could be done either by increasing the number of permanent members or by asking one or both of the existing European members - Britain and France - to relinquish their seats in favor of the EC.
Major and other British ministers strongly oppose giving up or sharing Britain's UN seat, and the current initiative is seen in government circles as a means of emphasizing that opposition.
Germany is extremely keen for the EC to project a jointly formulated foreign policy.
Last Friday its foreign minister, Hans-Dietrich Genscher, said in a newspaper interview that the EC should set up shared embassies in the 11 new commonwealth republics.
He told Mitteldeutsche Zeitung: "I would like to plead for setting up common EC representations in these new countries. On the one hand it would give us a stronger negotiating position, while on the other it would save us costs and personnel."
But the British Foreign Office has rejected this idea in all but consular activities. "Foreign policy is about the exercise of sovereignty, and the prime minister made it clear at last month's Maastricht EC summit that there are functions in that area that Britain is not prepared to abandon or share," said one London diplomat.