This video footage shows a police surveillance operation in Chesterfield in 1935.
Filmed by officers from a first floor shop window on the market place, it went on to become the first surveillance footage ever used in a British court.
Police spent over a week filming the activities of a group of illegal street bookies in the town. In total, 39 people appeared in court with 25 of them being discharged. The other 14 either received fines or bind-overs.
The footage is courtesy of the BFI National Archive and is available on the BFI Player. To see the full film, click here.