The FV4201 Chieftain was the main battle tank of the United Kingdom during the 1960s, 1970s and 1980s. A development of the Centurion, the Chieftain introduced the supine (reclining) driver position to British design allowing a heavily sloped hull with reduced height. A new powerpack and improved transmission gave it higher speed than the Centurion despite being heavier due to major upgrades to armour protection and the armament: this allowed it to replace both the Conqueror and Centurion while performing their roles effectively. It remained in service until replaced by the Challenger 1 which shared many of the Chieftain's features.
Chieftain Mk.11 is the Chieftain Mk.8 after completing all phases of "Totem Pole". Later upgraded with Stillbrew, 1984-86