The Royal Tank Regiment’s formation followed the invention of the tank. Tanks were first used at Flers in September 1916 during the Battle of the Somme in World War I. At that time the six tank companies were grouped as the Heavy Branch of the Machine Gun Corps (MGC).
Today, there are two regiments, the 1st and 2nd Royal Tank Regiments (1RTR and 2RTR). Today, half of 1RTR forms part of the Joint CBRN Regiment (together with No. 27 Squadron RAF Regiment) with the other half as a training unit, while 2RTR retains its role as an armoured regiment as part of 1 Mech Brigade.