This, coupled with a modern suspension and drivetrain, gave the Leopard superior mobility and cross-country performance compared to most other main battle tanks of the era, only being rivaled by the French AMX-30 and Swedish Strv 103.

The Leopard quickly became a standard of many European militaries, and eventually served as the main battle tank in over a dozen countries worldwide, with West Germany, Italy and the Netherlands being the largest operators until their retirement.

The Leopard was soon being purchased from Germany by a number of NATO members and other allies, including (in chronological order) Belgium (1968), the Netherlands (1969), Norway (1970), Italy (1971), Denmark (1976), Australia (1976), Canada (1978), Turkey (1980) and Greece (1981).

This is a liquid-cooled, 37.4 litre, ten-cylinder, four-stroke engine in the V-90 configuration with multi-fuel capability but which was typically run on diesel fuel (NATO designation F-54) consuming approx.

The tank suspension system has 14 independent torsion bars each with a control arm, and 10 hydraulic shock absorbers which are installed on the 1st, 2nd, 3rd, 6th and 7th pairs of road wheels.

The 1A1 added metal-rubber skirts along the hull flanks to protect against HEAT warheads, and the gun barrel was wrapped in a jacket to reduce deviation from thermal loads.

The gun mantlet received a wedge-shaped armoured cover made from welded steel plates and the engine's air intake system was improved.

The PZB 200 low light level television (LLLTV) system with IRS 100 infrared scanner was developed by AEG-Telefunken and mounted in a protective cage on the mantlet, above the main gun, creating the Leopard 1A1A2.

The next 110 vehicles in the fifth production batch were fitted with a new type of welded turret designed by Blohm & Voss, which was equipped with spaced armour (consisting of two steel plates with a plastic filling between them), and a wedge-shaped gun mantlet, resulting in the Leopard 1A3.

The PERI R12 sight improved the commander's efficiency, allowing him to acquire and relay targets to the gunner considerably faster in what can be considered the precursor to "hunter-killer" capability.

The large, box-like armoured enclosure for the EMES 18 primary sight was mounted on top of the turret, in front of the commander's hatch, and contained a fully stabilized (both in azimuth and elevation) head mirror which was used for the daylight vision channel (×12 magnification and 5° field of view), Nd:YAG laser rangefinder and a WBG-X thermal imager from Carl Zeiss.

Lifting hooks were welded to the hulls of early production vehicles which lacked them (first and second batches) and the driver's station received high pressure washers for his observation periscopes (later installed in most Leopard 1s in German service).

The original 830 hp (634 kW) diesel engine has been retained, but the gearing of the transmission had been lowered, reducing the vehicle's road speed to 32 km/h (20 mph), but increasing tractive effort to 250 kN (56,000 lbf).

When the MBT-70 program was ended, a further contract was offered under the name Boar (Eber), with an emphasis on using as many technologies from the MBT-70 as possible, but without the problematic XM150 152 mm (6.0 in) combined gun/MGM-51 Shillelagh missile launcher.

In 1971, the minister of defence, Helmut Schmidt, decided to abandon the Eber-project and build 17 prototypes of a Leopard 2, based on the Keiler design, which had a turret with spaced sloped armour.

The first Leopards arrived in Australia from West Germany in 1976, ending a selection and trial process against the US M60[11] series that started in 1971, when the army decided it needed a replacement for its British Centurions, which had served since 1952 and had been deployed during the Vietnam War.

In January 2023 the government sought to buy these back to give to Ukraine, however the purchase was delayed over a disagreement on price, with OIP wanting around €500,000 each to cover the cost to refurbish them to battle-ready condition.

Five or six Leopard C1 tanks had an extremely thick MEXAS appliqué armour kit applied, made by German firm IBD Deisenroth Engineering.

Aside from the requested add-ons, the biggest update for the Canadian Leopard tank fleet was the implementation of the Atlas-Elektronik EMES-18 Fire Control System module, which featured a similar computerized setup as the C1's SABCA FCS, a laser rangefinder, and thermal imager.

[24][25] The armoured squadron was intended to provide convoy protection, supporting Canada's Provincial Reconstruction Teams and other organizations equipped with lighter vehicles, and combat operations.

It was determined that the lack of adequate air conditioning, essential in the searing heat of Afghanistan, was degrading the tank crew's war fighting ability.

In 1989, an order for an additional 110 (used) German tanks (100 A3 and 10 A4) was placed, and the vehicles were delivered from 1992-1994,[37] partly through Conventional Forces Europe treaty AFV reduction requirements.

On 29 April 1994 near the city of Tuzla seven Danish Leopard 1A5 tanks were involved in a skirmish between UNPROFORs Nordic Battalion (NORDBAT 2) and Bosnian-Serb military forces from the Šekovići brigade.

[42][43] Italy had to replace an enormous number of M47 Pattons, with over 2,000 received from US stocks, but unlike other NATO members did not instigate a national project to achieve this.

They were equipped with US radio sets using US-style antenna bases and a Dutch-designed smoke discharger system consisting of six launchers grouped into three pairs on either side of the turret.

[47] The program was plagued by technical challenges with the new fire control system, which rendered a significant number of upgraded tanks inoperable for a period of time, and cost overruns.

Approximately 50 tanks were retained for various purposes, including to be used as monuments, museum pieces, targets for live weapons practice, driver training vehicles and other niche applications.

Rheinmetall and RUAG signed a tentative purchase agreement for these tanks before a formal application for their sale and export was made with Swiss government authorities.

[65][66] In June, the Swiss Federal Council formally rejected RUAG's request for an export permit, blocking Rheinmtall's acquisition and the Netherlands ability to buy the tanks for Ukraine.

German experts travelled to Poland and confirmed the tanks required repairs due to the extensive training the vehicles performed in the preceding weeks.