Arriving in Britain in May 1948, Josten set up a news agency, the Free Czechoslovak Information Service (FCI), to report on conditions behind the "Iron Curtain". The main focus was on Czechoslovakia, but in due course bulletins were produced about Poland, Latvia, Romania, Cuba, Tibet and other countries under Communist control, including Russia. His first major scoop was breaking the story of the Soviet atom bomb test in 1949. He published weekly bulletins in both Czech ("Čechoslovák") and English ("FCI"), and ran many campaigns to discredit the Czech Communist régime. Josten vehemently opposed any form of accommodation with Communist régimes and was sometimes criticised for being too rigid in his views.