The Observer Corps (later the Royal Observer Corps) played an important part in the Battle of Britain. When the Luftwaffe started to attack Chain Home – a string of radar stations – there was the potential for Fighter Command to have been left ‘blinded’ by this loss. However, the Observer Corps made up for this. When Fighter Command used the information from Chain Home and the Observer Corps, they could get fighters into the air within the 20 minutes time zone that they required for the fighters to reach their optimum flying height.
“Arguably the most valuable of the voluntary services during the Battle of Britain was the Observer Corps.” (Jon Lake)
While Chain Home tried to track down incoming enemy aircraft over the sea, it was not as effective at doing this once they had crossed land. It was the task of the Observer Corps to do just this – track enemy aircraft movements overland. Many of the volunteers for the Observer Corps were enthusiasts with regards to aviation; many were aircraft spotters and would have been well versed in identifying incoming Luftwaffe aircraft.
The RAF took over the Observer Corps in 1939. A retired Air Commodore was put in charge of it. There were five Observer Corps Areas, sixteen Groups and a Corps Headquarters located with Fighter Command at Bentley Priory.
The Observers on the ground used whatever devices they could find to estimate the height at which Luftwaffe formations flew and their bearing. Numbers and types of aircraft were also relayed back to a Group Headquarters. In these headquarters a ‘picture’ of what was developing was created and that information was sent to RAF sector, Group and Command Operations rooms. Combined with information from Chain Home and Chain Home Low stations, Fighter Command could assess which incoming raid needed most attention because of the threat it raised.
Observer Corps posted were manned for the duration of the war in Europe. Their posts were first manned ‘in anger’ on August 24th 1939. In 1941, The prefix ‘Royal’ was added to the Corp’s title in recognition of the work it did in the defence of Britain.