This combined the manoeuvrability of the Leopard with improved armour that would offer better protection against HEAT rounds while adding a new missile-firing gun able to engage Soviet tanks at very long range.

By this point, the only western tank able to go head-to-head with the latest Soviet types was the British Army's Chieftain, introduced to service in 1967.

However, the Chieftain had a number of problems due to its rather poor engine and outdated suspension, both of which conspired to make cross-country performance rather limited.

In 1977, Frederick Mulley, then Secretary of State for Defence, announced that, while both countries had agreed on the specifications of the joint tank, the replacement timetables diverged to such a degree that collaboration was not practicable at that time.

Notable was the 105 mm gun, which did not have the power to defeat the latest Soviet designs at long range, the preferred action for British tankers.

[i] This new project would build on work already carried out by the Military Vehicles and Engineering Establishment (MVEE) as far back as 1968, when they had produced a tank prototype with an external (unmanned) turret.

Other design features included the use of a David Brown Gear Industries TN-38 transmission, a Sperry/Vickers stabilised panoramic sight for use by the tank commander, and an advanced vetronics suite incorporating Ferranti F100-L microprocessors.

[3] The fire-control system (FCS) would access and process relevant target, environment, and gun status data from various internal and external sensors including laser rangefinders and thermal imagers, to help the main gun hit targets accurately and consistently under more adverse conditions: "First shot, first kill".

[m] Secondary armament would have included a 7.62 mm L37A1 General Purpose Machine Gun mounted on the commander's cupola, which could be aimed and fired from within the tank.

[1][3] The tank would also have had among other protection features a full active NBC defences, something that was becoming more common on military vehicles being designed and/or introduced in the late 1970s and early 1980s.

As a thermal signature management measure, the exhaust gases from the Rolls-Royce CV12 TCA Condor engine would have been mixed with cooling air before being discharged outside the tank.

The British defence industry was heavily reliant on the Iranian market, forcing the government to cut the number of workers at ROF Leeds.

In addition, there were increasing worries that Soviet tank technology was advancing at such a rate that new designs, such as the T-80, reportedly about to enter service would obsolete extant front line British MBTs far sooner than predicted formerly.

[2][3] Ultimately, the entire programme was cancelled in favour of the Challenger, which had been developed from the Shir 2 as a private venture,[s] and would be in theory available for service by 1983 to replace the Chieftain tanks instead.

[2][3] In the event though, the MBT-95[v] was superseded by the Challenger 2 programme in 1987[w] in part due to financial and political considerations and partly due to the unexpectedly poor performance of the original Challenger in early trials, exercises and the like[x] which seemed to indicate an urgent need for a replacement tank in the near term, and not just to replace the remaining Chieftains as originally planned.

The first, Automotive Test Rig 1 (ATR1), had a hull assembled from Shir 2 prototypes derived from the Chieftain, removable blocks of armour that either contained Chobham or steel designed to imitate it, and a dummy tank gun.