German air raids by Zeppelin airships and Gotha bombers on London and other British cities during World War I had shown the need for strong anti-aircraft (AA) defences in any future war.
By 1938, RHQ, 154 and 155 Batteries had moved from Chelsea to Artillery House, Horn Lane, in Acton, and were joined by a new 271 AA Battery based at Brentford, replacing 156 (Barking) Battery, which had become part of a new 82nd (Essex) AA Regiment[REF][REF] .