The 30 mm RARDEN Gun was developed by the Royal Small Arms Factory at Enfield Lock (which closed in 1988) and the Royal Armament Research and Development Establishment (now part of the Defence Evaluation and Research Agency) at Fort Halstead during the mid-1960s, and the first prototype was produced in 1966.

The first preproduction version was produced in 1968 and the first service versions appeared during the early 1970s. The design philosophy of the gun was that it should have a restricted rate of fire so that it could be installed in relatively light armoured vehicle turrets but still fire accurately enough to deliver a sufficiently lethal projectile to destroy APCs and similar vehicles at ranges of over 1,000 m.

Proven accuracy is such that 1 m groups at a range of 1,000 m are achieved on a regular basis.

The RARDEN L21 gun fires ammunition developed from the Hispano-Suiza 831-L round, former Royal Armament Research and Development Establishment (RARDE) and Royal Ordnance developed ammunition.

Under contract to the UK MoD Royal Ordnance was developing a new APFSDS-T round with enhanced performance. Due to technical problems development of this has been cancelled and a new competition will now be held.

The gun operates on the 'long recoil' principle in which the barrel and breech mechanism initially recoil together providing low trunnion loads. The empty cartridge case is extracted and a fresh round is loaded during the runout phase of firing. The system on the RARDEN is fully enclosed, and the internal section of the gun intrudes only 430 mm into the turret space. The gun can hold six rounds which are fed in three-round clips. The gun is charged by a small cocking/loading handle and spent cases are ejected forward from the gun. No firing fumes or cases can penetrate into the turret area. Normally, the gun fires single shots only but six-round bursts are possible. This ensures that the lightweight barrel has a low wear rate.

Recent production of the 30 mm RARDEN has been undertaken at Royal Ordnance Nottingham for the Alvis Vehicles (previously GKN Defence) Defence Warrior mechanised combat vehicle. Final deliveries of the Warrior were made to the British Army in February 1995.

The British Army also used the 30 mm RARDEN installed in a two-person turret on a number of FV432 APCs and on the Fox (4 x 4) armoured car, both of which have now been phased out of service.

The turrets from the Fox armoured cars have been removed and installed on refurbished Scorpion chassis with the new vehicle being known as the Sabre. The latter is now in service with the British Army in the reconnaissance role alongside the Scimitar which is also armed with a 30 mm RARDEN gun. The Fox remains in service outside the UK.

Production as required. Installed in the FV107 Scimitar; FV721 Fox; Warrior; Sabre. Total production of the 30 mm RARDEN cannon has now exceeded 1,600 units.