The Mk VIII was the light tank designed by Vickers-Armstrong to be the successor to the Mk VII Tetrarch for the British Army. The company intended that the Mk VIII would improve on the design of the Tetrarch in a number of areas, particularly that of armour protection. It had thicker armour than the Tetrarch, with the frontal hull and turret armour being increased to a thickness of and the side armour to , and the turret and hull were given more sloping surfaces than the Tetrarch to help deflect shells. The dimensions of the Tetrarch design were also changed, with the Mk VIII being longer by , wider by and its weight being increased; these alterations meant that the tank could no longer be air-portable, as it was too heavy to be carried by the General Aircraft Hamilcar glider.