London — Prime Minister Margaret Thatcher has insisted more strongly than ever that the current plan for uniting Europe must not destroy British sovereignty and national identity. This week she attacked a prediction by Jacques Delors, president of the European Commission in Brussels, that within the next decade the 12 Community members will be deferring to the European Parliament. Last week, Mrs. Thatcher replaced Britain's two commissioners to Brussels, one of whom has guided the evolution of the plan for a single internal market for Western Europe by 1992.
A senior adviser to Thatcher insists she is just being practical. He says she remains a committed European who welcomes the idea of a more economically integrated European market, as the 1992 plan calls for. But she has always opposed plans for a single European state and is dead set against any plans such as a European Central bank, or common currency.
Other political analysts here say Thatcher does not understand the rhetoric of European politics and the importance of making political concessions in order to reap economic benefits.
In a bold attack on the idea of a unified Europe, Thatcher told a BBC radio audience that ``you are talking about some airy fairy concept which will never come in my lifetime and I hope never at all.''
Her comments were directed at Mr. Delors, who said earlier this month that in 10 years 80 percent of social and economic legislation would be taken on a Community-wide basis rather than by national legislatures.
Thatcher said Delors had spoken more radically in public than he had with her in private. The prime minister was scornful of his statement that an embryo European government should be in place by the mid-1990s. She said she would never concede the majority of economic and social decisions to the Community.
Thatcher's opinions have popular appeal in Britain, where the advocates of European union are typically found among urban intellectuals rather than among rank-and-file members of the two leading political parties. As a nationalist who has valued Britain's special relationship with the United States rather than relations with continental Europe, the prime minister has long opposed the idea of political integration, popular during the 1950s. Her definition of economic integration has been more in terms of establishing a free market among than in coordinating economic policies.
``I think some people are being very superficial when they say there is a United States of America, why don't we have a United States of Europe?
``It is not possible to have a United States of Europe,'' she said in the radio interview. Revealing the extent of her nationalism, Thatcher identified herself with the late French leader, Gen. Charles de Gaulle, who firmly opposed a unified Europe. ``I was really very much with de Gaulle that this is a Europe of separate countries working together,'' she said.
This is not the first time the British prime minister has disagreed with Delors, but it is the first time a British leader has publicly rebutted a senior official of the European Commission. Some observers say she has overreacted. ``She seems unwilling to accept the fact that if someone is president of the European Commission they have to try to raise the level of political debate,'' said Helen Wallace of the Royal Institute of International Affairs. Other European leaders have let Delors have his say, then got on with their own agendas behind the scenes.
The eruption of the 1992 question this summer follows a long period of scant interest in the issue among British politicians. The reawakening has come as the European Commission becomes more aggressive in pushing the harmonizing of tax rates among Community members and with more talk of political integration.
``We're very worried that things have gone too far,'' said Theodore Taylor, a Conservative member of Parliament. ``They seem to have gone almost crazy with this idea of a united Europe.''
The prime minister signaled her reservations about the direction of Europe's economic integration last week when she nominated former Cabinet member Leon Brittan to replace Francis Arthur Cockfield as Britain's senior member of the European Commission.
Lord Cockfield had directed the steps toward a common internal market by 1992. Among other things, he disagreed with Thatcher on common tax rates.
Like Lord Cockfield, Mr. Brittan has held top Cabinet posts and is considered well qualified for the Brussels assignment. In a bitter personal criticism of Thatcher last week, former Conservative prime minister Edward Heath accused her of sending conflicting signals on Britain's commitment to the European Community.