The Chain Home radar tower in Essex has been granted listed status by the Department for Digital, Culture, Media and Sport (DCMS).
The 109-metre tower, which is located at Great Baddow near Chelmsford, was awarded the status to coincide with the 80th anniversary of the Battle of Britain in 1940.
Chain Home was the name given to a group of early coastal radar towers developed by the RAF.
In 1935 British radio pioneer Robert Watson Watt, and his assistant Arnold Wilkins, were asked to comment on reports of a German ‘death ray’ based on radio technology.
After investigating, they determined this was not possible, but Wilkins did come up with the idea of the air ministry being able to use radio waves to track aircraft. They then went on to carry out an initial trial using a BBC short-wave transmitter which proved successful.
Over the next couple of years a system was developed and built, and by 1938 a chain of radar masts was in place. They used a frequency radio of between 20 and 55MHz.
By 1939 at the start of WW2, the network was installed and put to use to track enemy aircraft, and was a key to UK defences in the Battle of Britain.
The mast still standing at Great Baddow was originally installed at RAF Canewdon, also located in Essex, but was moved to the Marconi company (now BAE Systems) at Great Baddow in 1956.
At its new location it was also used to develop further radar work during the cold war period.