[JURIST] Solidarity [Wikipedia article] founder and former Polish President Lech Walesa [BBC profile; Lech Walesa Institute foundation website] said Monday he has filed charges against Radio Maryja [radio website in Polish], a radical Roman Catholic radio station in Poland, over comments made on the stations that he collaborated with Communist Party authorities in the 1970s. Walesa, who filed the charges with prosecutors in the northern port city of Gdansk last week, said the station accused him of signing secret agreements with Communists and also working as an informer for Poland's secret police. Gdansk prosecutors had started an investigation into the matter after Walesa brought the incident to the attention of the nation's justice minister. Walesa led the Solidarity union protests which is credited with helping to topple communism in Poland in 1989-90. In 2000, a special court set up to check the records of officials running for public office, had cleared Walesa of any Communist activity in the 1970s. AP has more.