The work that Bletchley Park and MI6 did during World War Two, was instrumental in the allies’ victory.

But until now, there hasn't been any video showing what life was like on the sites dedicated to this work.

This all changed when a piece of film was anonymously donated to Bletchley Park Trust, providing an unprecedented insight into the lives of those there.

Produced by Gordon Corera and Olivia Lace-Evans