KEN DODD, editor of the Guardian, has described his own country, Britain, as "the least free and least democratic of any Western European country today." The reason for his chagrin is the Thatcher government's campaign to suppress reports on the memoirs of a retired intelligence agent, Peter Wright. For Americans exhausted by discussion and analysis of this country's national security operations this summer, the saga of Mr. Wright's book "Spycatcher" is a reminder of how very differently the two countries treat freedom of speech and of the press when the government tries to keep sensitive material secret.

Because of contractual obligations of secrecy binding on all government employees, "Spycatcher" was not published in Great Britain. The book contains some sensational charges, among them that intelligence agents conspired to discredit Harold Wilson's Labor government because they believed that prime minister was under the influence of the Soviets. The Thatcher government has tried to stop publication of the book in Australia, where Mr. Wright now lives, and has moved in court against newspapers both at home and in Hong Kong that have published excerpts from and descriptions of the contents. Last month, Britain's highest court of appeals upheld the government in proceedings against British papers and extended the ban to prohibit the publication of reports on evidence and arguments presented during the court hearings in Australia.

All this litigation may be useless in practical terms. The book has been published in the United States and copies of the American edition are being sold on the streets of London. And a former Labor Cabinet member has defied the government by reading the text of "Spycatcher" aloud at Hyde Park Corner.

The British government has had wide powers to suppress publications in the interest of state security or, some allege, to spare the government great embarrassment. This case has prompted debate on the wisdom of allowing such restrictions. It isn't easy to deal with sensitive information in a public forum, but it is even more difficult, notwithstanding the efforts of international litigators, to keep a secret in one country when it is published as news in another. Ask the people in Washington who saw their secret Iran dealings blown in a Middle Eastern newspaper last fall.