London — Britain's decision to follow the American lead and leave UNESCO has pleased the United States but has raised doubts among Britain's European and Commonwealth allies about its commitment to them. In announcing its intention to leave the United Nations Educational, Scientific, and Cultural Organization at the end of this year, Britain was echoing the US belief that UNESCO was too extravagant, too inefficient, and too highly politicized.
In financial terms, Britain's withdrawal is not all that significant. Its $8.8 million-a-year contribution amounted to less than 5 percent of the total budget, compared to the much heftier share of 25 percent provided by the US until it pulled out last year.
But Britain's withdrawal is still a blow to the prestige of the world agency, which counts Britain as its principal founding member and the provider of its first secretary-general, Julian Huxley.
The departure of both the US and Britain is not expected to start a stampede by other Western nations, however. Although the Netherlands and West Germany, from among the European countries, and Japan have similar misgivings about UNESCO, they are unhappy that the organization's lumbering efforts at reform have not gained it a temporary reprieve from Britain.
Despite French and West German entreaties, Britain decided to go ahead with its planned pullout on the basis that the reforms fell short of British demands.
Britain's go-it-alone policy is not likely to endear it to its European Community partners, particularly since Prime Minister Margaret Thatcher has been crusading for a united European voice on foreign policy issues.
The decision to line up with the Americans also confirms a deeply held suspicion that Britain will not put European interests ahead of its close US links.
Britain's Commonwealth partners are even more upset. They regard it as an anomaly that Britain, as head of the Commonwealth, should turn its back on UNESCO, which has such strong support in the developing world.
The British have attempted to show that this is not the case by announcing that funds would now be redirected through different channels to developing nations.
Yet after Britain's foot-dragging over sanctions against South Africa at the recent Commonwealth Prime Ministers' Conference, African countries in particular don't feel that Britain's heart is in the right place.
Even within Britain, the decision to pull out was widely opposed. Among Mrs. Thatcher's strongest critics were rank-and-file Conservative Members of Parliament.
Former Conservative Prime Minister Edward Heath, who takes his Conservative successor to task on practically every issue except Northern Ireland, anticipated early on that Britain would quit. It was a move he denounced as ``nasty, narrow-minded nationalism.''
The timing of the announcement, on the eve of US Defense Secretary Caspar Weinberger's signing of an SDI (Strategic Defense Initiative, or ``star wars'') agreement with Britain, has also increased the Labour Party's irritation with a Conservative government that it feels is too ready to cosy up to President Reagan.
Labour politicians have indicated that the Thatcher government's ``subordination'' to US defense policy will be an issue in the next general election.
An inkling of what might be in store is illustrated by a ``Gone with the Wind'' movie poster hanging on the walls of a Labour Party office in Liverpool.
President Reagan, with Clark Gable moustache and forelock, is shown carrying Margaret Thatcher.
``She promised to follow him to the end of the earth. He promised to organize it!'' the poster declares.
The ``Gone with the Wind'' 1985 political version is by ``Milton Friedman in association with Pentagon Productions.''