1. Britain's X-Files

Examining the UFO phenomenon in Britain since the 1950s, when alleged sightings began and Clement Attlee formed the Flying Saucer Working Party. The documentary recalls how UFOs became a symbol of the communist threat during the Cold War and - with access to previously secret files - shows how paranoia over these mysterious vessels struck at the heart of the political, military, and royal establishments. NEW SERIES 1/5.