The Poles call it the law of lustration, a term meaning ritual purification; the word has strong connotations of repentance and penitence in Poland, where history and Catholicism are so closely intertwined.

Under the law, which was passed last October and entered into force on 15 March this year, 700,000 Poles are required to confess any collaboration with the communists between 1945 and 1989. All senior civil servants, university professors, lawyers, headmasters and journalists born before 1972 must now confess their past sins by 15 May.

They must all fill in a form and answer the question: "Did you secretly and knowingly collaborate with the former communist security services?" The forms must be handed to their immediate superiors, who will forward them to the Institute of National Memory in Warsaw, which will check its records and issue a certificate of political purity. Journalists employed in any public service will be dismissed automatically if they collaborated. Anyone who refuses to answer the question or who is proved to have lied may be banned from their profession for 10 years.

This mad law, which is causing uproar in the European Union, makes the McCarthyites of the United States in the 1950s look like amateurs at the practise of anti-communism. It is the main feature of a witchhunt launched by the authorities after the conservative president, Lech Kaczynski, and his twin brother, prime minister Jaroskaw Kaczynski, came to power in Poland in October 2005.