The author reconstructs one of the largest operations undertaken by the Security Service in sixties. It was a part of various activities of communist authorities to limit contacts of Polish citizens with the West and Polish emigration. On of the most fiercely fought enemies was Radio Free Europe, which was successfully breaking the information monopoly of the Polish communist authorities. In 1963 Władysław Bartoszewski, who during the war was an AK (Home Army) soldier and activist of Council to Aid the Jews, and during the stalinism period was imprisoned for many years, began conspiracy co-operation with Radio Free Europe. With a group of co-operators (who were also ex-AK soldiers) he regularly passed to Munich information about situation in Poland – repressions and harassment against the intellectuals, Church, opposition. This information was the basis of numerous important programmes of Radio Free Europe. SB found the traces of his activities in 1966, using the bug information and intelligence sources. Bartoszewski and his co-operators were kept under meticulous surveillance for many years, SB tried to intimidate them, enrol for co-operation, isolate in their environments. Help of Stasi and KGB was used. The most important aims of Security Service was to discover „transfer channels” (ways of passing the information from Poland abroad) and to fi nd evidence which would allow to sue Bartoszewski. They succeeded only in 1970, when his co-operators: Stanisław Salmonowicz, Danuta Bańkowska, Ewa Dreżepolska were arrested. Władysław Bartoszewski was questioned many times and the Service tried to enrol him. After his fl at refusal, the Service used their net of secret agents to spread rumours and forged documents, which were to discredit Bartoszewski as a professed agent of Ministry of Interior. Simultaneously a lawsuit, which was to be a propaganda blow against Radio Free Europe, was being prepared. These plans were ceased only after dramatic events in Gdynia, Gdańsk and Szczecin in December 1970 and changes on the authorities’ top. New Gierek’s team, who wanted to present their „liberal” face withdrew plans for lawsuit and released the three arrested people. Nevertheless they were still, together with Bartoszewski, subject to harassment and surveillance. Bartoszewski continued his co-operation with Radio Free Europe.