Air Raid Precautions (ARP) refers to a number of organisations and guidelines in the United Kingdom dedicated to the protection of civilians from the danger of air raids. Government consideration for air raid precautions increased in the 1920s and 30s, with the Raid Wardens´ Service set up in 1937 to report on bombing incidents. Every local council was responsible for organising ARP wardens, messengers, ambulance drivers, rescue parties, and liaison with police and fire brigades.
From 1 September 1939, ARP wardens enforced the "blackout". Heavy curtains and shutters were required on all private residences, commercial premises, and factories to prevent light escaping and so making them a possible marker for enemy bombers to locate their targets.
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