Spying on the silent movie star, Charlie Chaplin
17 February 2012 Last updated at 07:57 GMT
Charlie Chaplin became the subject of a British intelligence investigation after the US pressed for evidence linking him to communism, according to files released in the National Archives.
When the movie star arrived in the UK in 1952, the US announced he would be banned from returning there. The FBI asked MI5 to find evidence he was a member of the communist party, but no evidence was ever found.
Gordon Corera reports.