The Royal Corps of Signals is one of the combat support arms of the British Army. Signals units are among the first into action, providing the battlefield communications and information systems essential to all operations. Royal Signals units provide the full telecommunications infrastructure for the Army wherever they operate in the world. The Corps has its own engineers, logistics experts and systems operators to run radio and area networks in the field. It is responsible for installing, maintaining and operating all types of telecommunications equipment and information systems, providing command support to commanders and their headquarters, and conducting electronic warfare against enemy communications.

Tactical recognition flash (TRF) is the British military term for a coloured patch worn on the right arm of combat clothing by members of the British Army, Royal Navy and Royal Air Force. A TRF serves to quickly identify the regiment or corps of the wearer, in the absence of a cap badge. It is similar to, but distinct from, the DZ Flashes worn by members of Airborne Forces.