The Challenger was a marked improvement over the Chieftain in terms of engine reliability, though was still not without problems. Developed at short notice from the Shir 2 intended for export to Iran, the Challenger was only ever a stop-gap measure intended to replace half of the Chieftain fleet until a better tank could be developed. Challenger and its Improved Fire Control System delivered a notoriously poor performance in the 1987 Canadian Army Trophy – a NATO tank shooting competition. In 1990/91, in preparation for Operation Desert Sabre, the Challenger underwent extensive modifications to enable it to operate in the desert environment, and had improved ammunition stowage and additional armour added to the hull front and sides. Challenger would ultimately perform well and achieve the longest ranged knock-out of an enemy tank ever recorded, at some 4,700 metres, albeit under relatively permissive conditions. (Artwork by David Bocquelet)