Pre-War Blackout Exercise - Night of August 9/10 1939

With the threat of war in the summer of 1939 building, a number of exercises were held to determine the effectiveness of the blackout. Trials like the one below were made across London to ascertain the effectiveness of the warden service to ensure the blackout regulations were followed. RAF aircraft flew over the 'blacked out' areas and reported that a lot of light was to be seen - especially when pub doors were regularly used.

Pre-War Blackout Exercise - Night of August 9/10 1939