Royal Air Force
Royal Army Service Corps. Now called the Royal Logistics Corps, the RASC was responsible for supply and transport in the army.
Royal Corps of Signals. Responsible for providing battlefield communications and information systems essential to all operations. A number of RCS officers and other ranks served in Auxiliary Units Signals, setting up and maintaining the secret wireless network.
Royal Engineers. The Corps of Royal Engineers provides military engineering and other technical support to the British Armed Forces. Special RE units assisted with the construction and wiring of operational bases and IN-stations of the wireless network
Royal Electrical & Mechanical Engineers. A British Army corps (formed in 1942) responsible for the maintenance, servicing and inspection of electrical and mechanical equipment.
Royal Observer Corps. A civil defence organisation, intended for the visual detection, identification, tracking and reporting of aircraft over Great Britain, operating between 29 Oct 1925 and 31 Dec 1995.
Civilians used by Special Duties Branch for picking up and distributing messages deposited in dead letter drops. Also sometimes referred to as Couriers.