London — With the US now criticizing the Soviet Union more sharply than ever, Washington's allies in Europe are under new pressure to redefine their own foreign policy strategies and to speak with a single voice.
In recent days, leading officials in Britain, West Germany, Italy and France have spoken out on the need they see to strengthen internal cooperation in Europe.
One strong feeling is that Europe must do a better job in offering much-needed advice and counsel to the Reagan team on such issues as the arms buildup of the Soviet Union, and also Afghanistan, Poland and the Middle East.
The Europeans now discussing what might be done include the most pro-US leader of them all, Prime Minister Margaret Thatcher, and the least fond of the US, President Valery Giscard d'Estaing of France. Also offering ideas are the foreign ministers of West Germany and Italy -- Hans-Dietrich Genscher and Emilio Colombo.
Discussions will now continue until the European Community summit in the Netherlands March 23 and 24, with both Mrs. Thatcher and Mr. Genscher putting their own views directly to Mr. Reagan in visits to Washington in February and March.
A strong impetus for change will come when Britain takes over the rotating presidency of the EC in June. For six months Britain will have a leading role in directing European foreign policy moves.
Foreign Minister Lord Carrington has already indicated he would like to see the EC set up a small group of foreign policy advisers, drawn from various countries, attached to the office of the president.
What is happening in Western Europe now is a long- drawn-out process, speeded by the Ronald Reagan's victory last November, of learning how to make Europe's voice count in the Western alliance.
Mrs. Thatcher, looking to increase Britain's role in Europe at a time when her opposition Labour Party favors an early British withdrawal, has just praised Mr. Reagan and urged more European closeness with Washington.
In a recent speech Mrs. Thatcher warned of the "dark reality" of the Soviet threat. The Prime Minister said Europe should:
* Recognize more clearly the role the US plays in guaranteeing Western freedom.
* Make sure Europe is doing "all we can" to contribute to the common defense.
* Ensure that trans-Atlantic arrangements to coordinate policies are kept in "perfect working order." They did not work well when the Soviets invaded Afghanistan, and now Poland is newly threatened.
West Germany's Mr. Genscher has suggested a new treaty on European union. He has given few details, but th idea seems to be that by debating a new treaty, a fresh spirit of European unity could emerge, and new cohesion for the future.
Mr. Colombo's call is for tighter links on defense -- not a revival of the European defense community, which was floated and then killed in the mid 1950s, nor a threat to NATO. Rather, the Italians are seen as wanting recognition that the EC and the US have similar but different interests and that Europe should better define its own. President Giscard of France said a few days ago that political cooperation within the EC must improve, though, as usual, he is interested in strengthening France's own voice, and wants any new institutional structures on foreign policy established in Paris.
Chancellor Schmidt is reported to be not unduly concerned at President Reagan's recent harsh criticism of Moscow. The Germans are said to believe Mr. Reagan is less bellicose than his rhetoric might suggest and that he will grow more moderate in office.
Europe is deeply concerned at the threat to Poland and also wants to involve the Palestine Liberatio n Organization more deeply in the search for a Middle peace