Tank origin

The Shir 2 was a variant of the Chieftain main battle tank developed for export to Iran in the 1970s. With the end of the Iranian Revolution in 1979 and the subsequent regime change, however, the project was cancelled. At the same time, the UK dissolved its MBT-80 project due to expenses. These factors led the British Army to repurpose the Shir 2 and accept it into service under the Challenger name in 1983. With its 120mm rifled gun and Chobham composite armor, the Challenger served as a notable upgrade to the Chieftain.