The Chieftain was a radical evolutionary development of the successful
Centurion line of tanks that had emerged at the end of the Second World
War. The British had learned during the war that their tanks often
lacked sufficient protection and firepower compared to those fielded by
the enemy, and that this had led to high casualty levels when faced with
the superior German tanks in World War II. Chieftain was designed to be
as well protected as possible and to be equipped with a powerful 120 mm
rifled gun. The heavy armor came at the price of reduced mobility,
chiefly due to engine power limitations, which was perhaps the
Chieftain's main drawback.