In 1977, the Iranian government ordered an improved version of the Chieftain tank, which was arguably the best main battle tank (MBT) in service at its time. The Chieftain offered unparalleled protection and firepower; however, its mobility was lackluster and something its successor needed to improve upon. In response, the engineers at the MVEE created the Chieftain Mk.5(P), from which three additional prototypes were created. It was one of these prototypes that would become the basis for the Challenger 1. Unfortunately, after the Iranian Revolution of 1979 and the fall of the Shah, Iran canceled its order for an improved Chieftain. In addition, a parallel British tank project (the MBT90) was also abandoned, and the British Army quickly became a new potential customer for a new MBT.

The Challenger’s design was based on the cancelled project called “Shir-2” planned for export to Iran, and retained its deadly 120mm gun and superb armour. The Challenger was also equipped with Chobham armour, a composite armour made from multiple layers of different materials. The additional materials gave the Challenger its distinctive, heavily-sloped armour on the front of the turret and upper glacis. The Challenger’s mobility and off-road capabilities were significantly improved with the installation of a new 1,200 horsepower Rolls-Royce engine and hydropneumatic suspension. The Challenger 1 entered production and service in 1983. Production ended in 1990, having yielded a total of about 420 vehicles. It served primarily with British forces during the Gulf War. It was also used in peacekeeping missions in Bosnia-Herzegovina during the mid 1990s, and Jordan still operates a number of Challenger 1 tanks to this day. The Challenger 1 was withdrawn from active service by 2001 and later replaced by the Challenger 2.