It was the UK which developed and introduced the Centurion as what may be regarded as the world’s first main battle tank. The UK had learned the lessons of modern armoured warfare in World War II, and found that almost all the cruiser and infantry tanks it created were inferior in at least one of three three parameters which drove (and indeed still do drive) the design of the tank of whatever type. Entering British service in 1949, the Centurion could trace its immediate conceptual origins to the A34 Comet cruiser tank, but with a larger hull and, just as importantly, a larger turret ring which allowed the Centurion to be steadily upgunned: The initial Centurion Mk 1 was armed with a 17-pdr (77-mm/3.03-in) gun, the Centurion Mk 3 introduced the 20-pdr (84-mm/3.31-in) gun, and the definitive Centurion Mk 5/2 introduced the classic L7 gun of the 105-mm (4.13-in) calibre that became standard for most of the Western world’s main battle tanks for many years.
The hull and dynamic system (engine, transmission, suspension and tracks also proved very successful, and was used in revised forms as the basis of self-propelled artillery weapon prototypes, the FV4004 Conway prototype for a heavy tank armed with a 120-mm (4.72-in) gun, and the FV4005 prototype for a tank destroyer armed with a 183-mm (7.20-in) gun. Special-purpose variants were also developed, and those which entered service were two bridgelayers, an Armoured Vehicle Royal Engineers with specialised assault equipment as well as a 165-mm (6.5-in) low-velocity demolition gun, two armoured recovery vehicles, an armoured ramp carrier for bridging larger gaps, a beach armoured recovery vehicle and a bulldozer.
In other countries, most especially the USSR and USA, there were large numbers of comparatively new and effective World War II tanks of indigenous design and construction still in service, and it was this factor which made the USSR and USA slower to embark on the development of their own main battle tanks. By the late 1940s these World War II designs were no longer competitive, however, especially for combat arenas in which weapons with shaped-charge warheads might be used, and they used their major design and production capabilities to introduce a new generation of main battle tanks.
Vast numbers built
First off the mark was the USSR, which introduced the 79,365-lb (36000-kg) T-54 main battle tank in 1950 as what was in essence a development of the T-44 experimental tank of 1944 with a 90-mm (3.54-in) gun but incorporating a number of improvements suggested by the last years of combat in World War II and armed with a 100-mm (3.94-in) gun. This led to the improved T-55 of 1960, and it is estimated that production of the T-54 and T-55 series, in China and Czechoslovakia as well as the USSR, may have reached between 85,000 and 100,000 vehicles. This makes the T-54 and T-55 series the most extensively built tank of all time: by contrast, production of the Centurion series between 1946 and 1962 totalled 4,423 vehicles.
The US counterpart of the T-54, but intended only as an interim type for service from 1942, was the 101,775-lb (46165-kg) M47 Patton fitted with a 90-mm (2.95-in) gun. Despite its origins as an interim type, the M47 was built to the extent of more than 9,000 vehicles.
The M47 was followed in US service by the M48 Patton, which resembled its predecessor in external shape but was an entirely new design which entered service in 1953 as a 104,000-lb (47175-kg) type armed with an improved 90-mm (2.95-in) gun which was later replaced by a version of the British 105-mm (4.13-in) weapon. The M48 was built to the extent of about 12,000 vehicles and, like the preceding M47, was also used as the basis of a large number of specialised variants analogous to those of the Centurion series.
Interim or not?
Though now often regarded as main battle tanks, all of these types were initially seen as medium tanks in the line of conceptual succession from the medium and battle tanks of World War II, In the 1960s, however, the concept of the medium tank was gradually but steadily evolved into that of the modern main battle tank. The spur for this development was the realisation that these medium tanks could carry guns in the calibre range between 90 and 105 mm (22.95 to 4.13 in) which were capable of penetrating any practical level of armour at long range. There were at the time still a number of very heavily armoured heavy tanks, but these were so massive that they were unable to use most existing bridges. The World War II concept of the heavy tank, armed with a very powerful gun and protected by very thick and therefore heavy armour, was clearly now obsolete. They were more expensive to manufacture and operate than the medium tank-derived first-generation main battle tanks such as the Centurion, T-54 and T-55, and M47 and M48, but were just as vulnerable as these vehicles to incapacitation (especially in mobility) if not outright destruction by anti-tank mines, air-dropped bombs, air-launched rockets and artillery. The revision on the thinking of the nature of the tank also suggested at this time that lightly armed and armoured tanks were of limited value in most roles on a high-intensity battlefield of the type likely to be fought by the major powers. Even though reconnaissance vehicles had tended toward greater weight and heavier firepower during World War II, it had now become abundantly clear that speed was not in itself an adequate substitute for protection and firepower.
It was this thinking which led to the creation of the second, and arguably first definitive, generation of main battle tanks.