The Vickers Medium Mark.III tank was a brief footnote in British tank development. Only three were built for trials purposes and it was intended that they would replace the previous Mark.II. Despite being the spiritual successor to the Medium Mark.II the two vehicles had very little in common and was one of a number of multi turreted designs that several tank manufacturers the world over had taken an interest in during the 1930s.
The origins of the tank can be traced back to 1926 when the War Office wanted a replacement for the proven but increasingly obsolete Mark.II tank which had served the Army well after World War I. There was an increasing interest in multi turreted designs (particularly in Britain and the Soviet Union) and as such a new design was drawn up comprising of four turrets;
- A single 3 pounder (47mm) gun in a central turret as the main weapon with two crew. This turret was powered and had separate cupolas for the commander and gunner.
- Two one-man turrets mounted at the front armed with single .303 machine guns for use against infantry. These were manually trained and induced high fatigue on the operators.
- A fourth turret was mounted behind the main turret and was equipped with an anti-aircraft gun.
The result was an extremely complex vehicle designated “A6” that was wrought with problems. It was underpowered even after efforts to re-engine it and a plan to combine two Rolls-Royce engines was shelved on cost grounds. Suspension problems made for an uncomfortable ride and testing showed that it was inferior to the Mark.II making it a poor gun platform.
Development of the A6 was discontinued in 1929 and Vickers reworked their design which resulted in the Mark.III. This had a similar arrangement to the A6 but with the deletion of the AA gun turret and the two machine gun turrets being moved further forwards. Armour ranged between 9 and 14mm in width which was adequate for the time but quickly becoming obsolete. While improvements were made in most areas the new type still suffered from the chronically bad suspension that plagued the A6. A third prototype would alleviate this problem with a new set up but by then the Mark.III had failed to win an order and it served for trials purposes only.
Despite the fact it never entered production the third prototype with its improved suspension was taken briefly in to service as a command vehicle and was used by Brigadier Percy Hobart on a military exercise at Salisbury Plain in 1934. After that the prototypes were scrapped.
Although an interesting design the type would certainly have been of little use against equivalent types with its thin armour and clumsy performance but it can be argued that development was not complete and therefore an accurate comparison can’t be made. The multi-turreted tanks of the 1930s were almost universally a failure but they could have been used as an infantry support vehicle with their mix of weapons.