This backwards looking tank was actually very effective

At first sight, the Valentine Archer isn't a terribly odd looking vehicle. The fighting compartment and gun appear to be at the rear with the barrel extending over the front deck; but they're not. In fact, the fighting compartment is at the front of the vehicle and the gun faces backwards over the engine deck in the rear. This odd-looking vehicle was the Vickers-Armstrongs solution to the problem of mounting the heavy, but effective, 17-pounder anti-tank gun in a fighting vehicle; this is the Archer.

Early in the war, Britain quickly learned that the majority of the guns mounted on its armored vehicles were inferior to the firepower that their German counterparts brought to bear. In early 1943, prototypes of the new Ordnance Quick-Firing 17-pounder anti-tank guns were sent to North Africa in response to the appearance of heavy German Tiger tanks. The gun proved to be effective against German armor; the problem was that it was heavy and had to be towed around the battlefield. Britain's new problem became mounting the 17-pounder on a mobile fighting vehicle.

Although projects were in development to mount the gun on a turreted tank (which led to the Challenger and Sherman Firefly tanks), the British Army needed to develop a vehicle that could carry the gun as quickly as possible. Vickers-Armstrongs was given the challenge and elected to use the outdated Valentine tank as the base of this new vehicle; its official designation being Self Propelled 17pdr, Valentine, Mk I, Archer. The Valentine's engine was upgraded to a GMC 6-71 6-cylinder diesel with a higher power output of 192 bhp in order to carry the heavy gun without sacrificing mobility. Still the gun could not be mounted in a turret and was instead mounted in a low, open-top armored fighting compartment. As previously stated, this was at the front of the vehicle with the gun facing backwards.

The mounting of the 17-pounder in the Archer allowed for 11 degrees of traverse and elevation from -7.5 to +15 degrees. If the gunner required more lateral traverse, the driver would have to physically turn the vehicle. As a result, the driver would remain at his station (facing the opposite direction of the action) at all times. Aside from this, it would be difficult for the driver to get in and out quickly because of the tight confines of the fighting compartment. The gun took up a lot of space and recoiled in the direction of the driver's head. That said, he was never in any danger of being struck thanks to the hydraulic recoil system that kept the gun well-clear of his head when it recoiled.

Although its odd layout was the product of necessity, it actually made the Archer an effective ambush weapon. An Archer could set up in a concealed position, fire at a target, and then quickly drive off in the opposite direction without having to turn around since it was already facing backwards. It had a top speed of 20 mph and was very adept at cross-country driving and climbing slopes.

Commonwealth military doctrine labeled the Archer as a self-propelled anti-tank gun rather than a tank or even a tank destroyer. As such, it was operated by the Royal Artillery rather than the Royal Armored Corps. The soldiers of the Royal Artillery eventually complained about the lack of overhead cover in the fighting compartment which led to the development of an optional armored roof. However, this addition saw very little, if any, use.

By the end of the war, a total of 655 Archers had been produced. After the war, the Archer saw service in Germany with the British Armored Corps in the British Army of the Rhine. 200 Archers were also supplied to the Egyptian Army with another 36 going to the Jordanian Arab Legion and National Guard.