The British Army had developed two types of tanks - "Infantry Tanks" which were heavily armoured with good all terrain performance but were slow. This lack of speed was not considered a flaw as they were designed to support infantry assaults on enemy strong points or urban warfare where the ability to outpace a man on foot was deemed unnecessary. The other type were "Cruiser Tanks" which were intended for independent maneuvering, rapid breakouts and flanking attacks. Early Cruiser tanks gained performance at a cost in the armour they could carry. Reliability was an important issue especially in the harsh conditions of North Africa and the mountainous terrain of Southern Europe, where the A10 and A13 in particular were plagued by broken tracks and overheating engines.