CHICAGO (AP) _ Former British Prime Minister Margaret Thatcher on Monday attacked the idea of a federated Europe.

Speaking to the Chicago Council on Foreign Relations, Thatcher reiterated her stand that the European Community should reach out and admit the emerging democracies of Eastern Europe.

She accused some EEC leaders of blocking overtures to the East because of narrow, protectionist trade concerns.

''If the new Europe were to follow a protectionist path, it would divide the world,'' she said. ''We in Britain want to include the new Eastern European democracies.

''A new wall - a wealth wall - has arisen in Europe to replace the Berlin Wall,'' Thatcher said of Western European leaders who often outvoted her 11-1 in past summits on greater European unity.

Thatcher resigned Nov. 28 and was succeeded by John Major as prime minister and head of the Conservative Party.

Thatcher said the Persian Gulf crisis and the muddled response of most Continental governments demonstrated the ineffectiveness of ''committee leadership'' and the need ''to preserve the Western alliance under undisputed American leadership.

''Twin victories - in the Cold War and in the Persian Gulf War - mean that our prospects for peace and stability are better than at any time since 1945,'' she said.

Such stability, Thatcher said, is possible only through the ''willing cooperation between proud nation states.

''What I find distressing about the EEC is not that it is international, but that it subverts so much real internationalism,'' said Thatcher, citing NATO and the American-British common stand in Operation Desert Storm as examples of ''real internationalism.''

She cited Yugoslavia and the Soviet Union as examples of internationalism at the expense of legitimate claims of national identity.

''These futuristic states have been exposed as dangerously unrealistic,'' Thatcher said, noting dissent and disunity in those nations.

Thatcher made only slight reference in her speech to proposals for a unified European currency, but she spoke directly on the issue in response to a question from the audience.

''It is the view of our country that we will not have a single European currency forced upon us,'' she said.

Thatcher noted that one of the initial purposes of the British Parliament was to oversee the soundness of the currency and protect it from meddling by the monarch.

She also said that a unified currency would not only be a dangerous check on British sovereignty, but could hurt the economy and future of the less developed areas of Europe.