Throughout the Battle of Britain, the Observer Corps constituted Britain's only means of aircraft detection over land, providing crucial intelligence to the early warning system enabling Britain to survive the summer of 1940. The largely volunteer organisation had its origins in the Zeppelin and Gotha bombing raids of the First World War and continued to expand through the inter-war period alongside the RAF. The Corps, coupled with radar, formed the system upon which the successful functioning of the RAF depended.
The chief duties of the observers ranged from the detection and identification of aircraft to the provision of navigational aids for Bomber Command, reporting of downed aircraft, location and timing of enemy raids as well as the status of aerial battles and the location of airmen forced to bail from their aircraft. Despite the Corps' unspectacular contribution to the defence of Britain, the defensive system would not have been able to function were it not for the 'eyes and ears' of the RAF. Overshadowed by Fighter Command and radar, the observers held an integral position in Britain's defensive system.