The Committee was appointed at the request of the military authorities to provide a direct link with civilian authorities and populations in the event of an invasion. It was composed of the existing members of the County Emergency Committee together with the Area Commander, Home Guard Zone Commander, County Controller and Chief Constable. The Controller and Committee were given full executive powers to act on behalf of the Council. A system of Area and Local Defence Committees (representing essential services in each town or village) was set up to prepare for invasion and ensure compliance with military instructions. They were later called Invasion Committees.
Records of local defence/invasion committees can be found in parish, borough or district archives.