The Cromwell tank, officially Tank, Cruiser, Mk VIII, Cromwell (A27M), was one of the series of cruiser tanks fielded by Britain in the Second World War. Named after the English Civil War leader Oliver Cromwell, the Cromwell was the first tank put into service by the British to combine high speed from a powerful and reliable engine (the Rolls-Royce Meteor), and reasonable armour. However the originally proposed dual-purpose high velocity gun could not be fitted in the turret and the medium velocity dual purpose gun fitted proved inadequate. An improved version with a high velocity gun became the Comet tank.

The name "Cromwell" was initially applied to three different vehicles during development. Early Cromwell development led to the creation of the A24 Cavalier. Later Cromwell development led to the creation of the competing Tank, Cruiser, Mk VIII, Centaur (A27L) design. The Centaur tank was closely related to the Cromwell, both vehicles being externally of very similar appearance. Cromwell and Centaur differed in the engine used. While the Centaur had the 340 hp Liberty engine, the Cromwell had the significantly more powerful 600 hp Meteor.

The Cromwell first saw action in the Battle of Normandy in June 1944. The tank equipped the armoured reconnaissance regiments of the Royal Armoured Corps, in the 7th Armoured Division, 11th Armoured Division and the Guards Armoured Division. While the armoured regiments of the latter two divisions were equipped with M4 Shermans, the armoured regiments of the 7th Armoured Division were equipped with Cromwell tanks. The Centaurs were not used in combat except for those fitted with a 95mm howitzer, which were used in support of the Royal Marines during the amphibious invasion of Normandy.

While that is all very interesting, what about the Centaur? Well, despite over 1,400 Centaurs of various marks being produced, only some of the 114 of the Mk.IV actually saw combat. The rest being used for training.