ended. In comparison, the current British MBT, the Challenger 2, weighs some . Interbellum British tank designs in the immediate post-World War I era were developments along the same design as the Mark A and were named as Mediums being around . The first tank to enter service that broke with the design was known as the "Vickers Light Tank" (it weighed about ). It was renamed as the Medium Mark I in 1924 as the earlier heavy and medium tanks went out of service and lighter tanks – or less – came into service. World War II In World War 2, Light, Medium, and Heavy tank applications to different roles were incorporated into doctrine. In the US, light tanks were expected to be used ahead of the main force, medium tanks to accompany the main thrust of attack, and by-their-nature slower heavy tanks being brought up to deal with any more significant opposition. In practice, US heavy tanks saw limited use due to the capacity limits of most dockyard equipment, preventing their delivery to the theatres of operation. This left a role-based classification, the tank destroyer, to evolve from the need to move artillery pieces and set ambushes for axis tanks. A variety of super-heavy tanks were also designed during World War II, although none ever saw combat or construction due to their impracticality. The British retained some light tanks from the interbellum period, but otherwise moved to a new role based classification scheme. Other countries started to move to a more role-based approach, for example, by categorizing tanks into cruiser tanks, breakthrough tanks, and fast tanks. The tanks themselves are still often referred to by light, medium and heavy weights based on the actual weight or the equivalent role (for example, a cruiser tank may be light weight but is used in a similar role to a medium). This continued until multi-role vehicles became available. Modern Light tanks, such as the PT-76, continue to play an important role in tank warfare, however many are being replaced with IFVs and armoured cars. The light tank is still more used than main battle tanks in many armies for various reasons: financial, terrain-related (muddy landscape and dense foliage), or doctrinal dependence on airborne divisions. Many light vehicles, such as the British Combat Vehicle Reconnaissance (Tracked) series (FV101 Scorpion, FV107 Scimitar) are used primarily for reconnaissance, but retain the tank capabilities. Medium