Chieftain Mk. 6

As larger and more powerful Soviet tanks became known, it was decided a replacement for the Centurion was needed. Design work began in 1958 and it was accepted for service in 1963. When introduced, the Chieftain was the best armed and armored tank available to NATO forces, although early versions suffered engine issues. The Chieftain underwent various improvements and variants until its replacement by Challenger 1 in the 1980s. It saw exportation and service in the Middle East where some remain in operation.