The cruiser tank (sometimes called cavalry tank or fast tank) was a British tank concept of the interwar period for tanks designed as modernised armoured and mechanised cavalry, as distinguished from infantry tanks. Cruiser tanks were developed after medium tank designs of the 1930s failed to satisfy the Royal Armoured Corps. The cruiser tank concept was conceived by Giffard Le Quesne Martel, who preferred many small light tanks to swarm an opponent, instead of a few expensive and unsatisfactory medium tanks. "Light" cruiser tanks (for example the Cruiser Mk I) carried less armour and were correspondingly faster, whilst "heavy" cruiser tanks (such as the Cruiser Mk II) had more armour and were slightly slower.