The British Pathe video above is incorrectly dated – the communist coup d’etat of Czechoslovakia happened on 25 February 1948, and this resignation speech from Slavik was likely from late February, early March, 1948. Vladimir “Vlado” Klementis was a member of the Czechoslovak Communist Party, and he became Foreign Minister on 14 March 1948 – taking over the position of Jan Masaryk (son of the first President of Czechoslovakia), who was murdered 4 days earlier on 10 March 1948, defenestrated in Prague, in the old tradition.

From NYT, 5 March 1948, “Czech Envoy to U.S. Who Resigned Is Berated Over Phone by Minister; Klementis, Deputy Foreign Chief of New Regime, Says He Is ‘Finished’ With Slavik — Third Diplomat Quits Post Over Coup”:

“WASHINGTON, March 4 — Dr. Juraj Slavik, who has resigned as Czechoslovak Ambassador to the United States rather than serve “a police state,” was denounced over the telephone by Vladimir Klementis, Czechoslovak Deputy Foreign Minister and a member of the Communist party, as soon as word of his resignation had reached Prague.[…]”