The Civil Defence Corps (CDC) was a civilian volunteer organisation established in Great Britain in 1949 to mobilise and take local control of the affected area in the aftermath of a major national emergency, principally envisaged as being a Cold War nuclear attack. By March 1956, the Civil Defence Corps had 330,000 personnel. It was stood down in Great Britain in 1968, although two Civil Defence Corps still operate within the British Isles, namely the Isle of Man Civil Defence Corps and Civil Defence Ireland (Republic of Ireland). Many other countries maintain a national Civil Defence Corps, usually having a wide brief for assisting in large scale civil emergencies such as flood, earthquake, invasion, or civil disorder.
Although under the authority of the Home Office, with a centralised administrative establishment, the corps was administered locally by Corps Authorities. In general every county was a Corps Authority, as were most county boroughs in England and Wales and large burghs in Scotland. The CDC was never established in Northern Ireland. Each Corps Authority established its own Division of the corps.
Each division was divided into several sections:
In London the City of London and London boroughs were Corps Authorities, but their divisions only had Headquarters, Warden and Welfare Sections. The London County Council organised the Rescue and Ambulance and First Aid Sections centrally and also shared responsibility for the Welfare Sections.
Members of the corps were issued with dark blue battledress and berets. A system of horizontal bars and point-down chevrons was used to indicate rank.