The Civil Defence Service was a civilian volunteer organisation in Great Britain during World War II.

Established by the Home Office in 1935 as Air Raid Precautions (ARP), its name was officially changed to the Civil Defence Service (CD) in 1941.

The Women's Voluntary Service (WVS) aided in ARP and observer duties as well as running and operating the mobile canteens and rest centres.

From the formation of the ARP until 1939, the badges were made of solid sterling silver, with a crescent-shaped button hole attachment for men and a pin style brooch for women.

Civil Defence insignia included a circular breast badge worn on the left pocket incorporating the letters "CD" topped by a king's crown (in yellow on dark blue or black backing).

On 10 June 1945, before His Majesty King George VI, a farewell parade with representatives of all the Civil Defence Services from across Great Britain took place in Hyde Park, London.