Great Britain Is Set Up for a Down-Sizing : Parliament: Scots, Welsh and Ulstermen have a good chance to cut nationalist deals in next month’s election; the queen is not amused.

This could be the year of the last traditional British election. In the vote for members of Parliament on April 9, the policy differences between the Conservative and Labor parties will be the smallest for 30 years. The result, however, could be the farthest-reaching of any vote this century.

Opinion polls predict a stalemate. If no party has a parliamentary majority, the deal-making begins. Would-be prime ministers will offer sweeteners in return for support. Powerful forces in Scotland, Wales and Northern Ireland will then be standing by to begin the breakup of the United Kingdom in its current form.

Why is this happening? Because ideological conflicts are dead or dying in Britain as elsewhere. Firm government is out of fashion. Conservative Prime Minister John Major is to Margaret Thatcher what George Bush is to Ronald Reagan--a pale compromiser. Labor Party leader Neil Kinnock used to be red in tooth and claw. But now he has pale pink fingernails like the rest of us. British elections used to be about whether to kick the Yanks out, take industry into public ownership and allow trade unionists to run the country. For the next few weeks--a blessedly short time at least--the arguments will be about the need for three Trident-carrying submarines or four, taxation for the middle class, health-care formulas and German industrial relations models.

Major is the first prime minister since the invention of opinion polling to go voluntarily for reelection when the poll data predict that he will lose his majority. He took the decision this week in the belief that delaying until June, the last legally possible month, would look like a funk and send financial markets and his own future prospects even faster southward.

Labor has to take at least 100 additional parliamentary seats to have a decisive majority. Few think they can do that in one election. So a likely outcome is a “hung Parliament” with unusual power available to smaller parties, the Liberal Democrats, the Scottish and Welsh Nationalists and Ulster Unionists, all of whom want some degree of constitutional change.

Small countries are the fashion of the 1990s. Scotland has long chafed under the English yoke, all the while absorbing huge English subsidies as it moans. But when the Scots see Croatia, Slovenia, Estonia, Cyprus and Malta queuing for independent membership of the European Community, they think “why not us?”

Major visited Scotland recently and threatened the rebels that they had to choose between staying in the United Kingdom entirely or leaving it entirely. His Conservative Party, unlike Labor, would not be offering sops to national self-rule.

But by April 10, Major is likely to control only one of the 70-plus Scottish members of Parliament; the rest will be divided among Labor, Scottish Nationalists and Liberals. The latter will be offering support in return for a new proportional representation voting system in all future elections. Anything could happen.

Labor’s Kinnock was once a staunch supporter of an unchanged United Kingdom. Socialist principles have always demanded the largest possible canvas on which to wreak havoc, and Kinnock, stout Welshman though he is, was for most of his life an orthodox socialist. But the Labor leader can feel which way the nationalist wind is blowing. He has ditched most of his other principles in order to make himself electable. So why not have a new electoral system and a Welsh assembly?

The last bastion of old-fashioned statist principles in Europe is the European Commission, in which a vast bureaucracy, answerable predominantly to itself, manipulates increasingly intrusive transnational laws. Labor, which for years was hostile to the Common Market because it was hostile to all markets, is now very European.

Thus EC headquarters in Brussels may soon become the bureaucratic site of a British civil war. English officials will argue that Scotland cannot come in because London has a veto. Scots may retort that since England and Scotland came together in voluntary union in 1707, their voluntary parting should require both countries to renegotiate membership in the EC. Why should London assume that it, and not Edinburgh, has the right to the EC seat and the veto?

Those who want to guarantee the continuing United Kingdom hope for a clear Conservative victory next month. Their number includes the queen, who has quietly let it be known that she, at least, will not stand idly by while the country falls apart.