The company had achieved a degree of standardization with their previous five models, and the Mark VI was identical in all but a few respects.

[1] It had the Horstmann coil-spring suspension system, which was found to be durable and reliable, although the fact that the tank was short in relation to its width and that it pitched violently on rough ground made accurate gunnery whilst moving exceptionally difficult.

The Mk VIA had a return roller removed from the top of the leading bogey and attached to the hull sides instead, and also possessed a faceted cupola.

[7] The Mk VIC, which was the last in the MK VI series, had the commander's cupola removed and had wider bogies and three carburettors to improve engine performance; it was also more powerfully armed than the other models, replacing the .303 and .50 Vickers machine guns with co-axial 15 mm (0.59 in) and 7.92 mm (0.312 in) Besa machine guns.

The Tank, Light, AA Mk I was built in the aftermath of the Battle of France and was intended to act as a counter-measure against attacks by German aircraft.

[8] A variant on the Mk VIB was produced for service with the British Indian Army, in which the commander's cupola was removed and replaced with a hatch in the turret roof.

[11] When the Battle of France began in May 1940, the majority of the tanks possessed by the British Expeditionary Force were Mark VI variants; the seven Royal Armoured Corps divisional cavalry regiments, the principal armoured formations of the BEF, were each equipped with 28 Mk VIs.

In September 1941 the division deployed to Army Group North in Russia where they provided valuable service during the winter 1941–42 battles.

The same armoured unit had previously embarked three MK VIB tanks for the Norwegian Campaign, but they were lost in transit to a German aircraft attack.