The Air Defence Experimental Establishment (ADEE) was a civil agency run by the British War Office, the civilian side of the British Army.
In 1923 it moved to RAF Biggin Hill and in 1924 was renamed the Air Defence Experimental Establishment.
In 1941 it was joined by another development group known simply as the "Army Cell" that had been working on radar systems at Bawdsey Manor.
The two groups were merged to become the Air Defence Research and Development Establishment (ADRDE).
The radar groups from the Air Ministry, by this time known as the Telecommunications Research Establishment (TRE), moved to nearby Swanage that same year.