The 17 pounder anti-tank gun was a very powerful gun but also very large and heavy and could only be moved about the battlefield by a vehicle. This meant that it was more effective in defence than in the attack. Therefore there was the intention to mount it on a vehicle to give it more mobility. The Valentine chassis was soon chosen for this role, as it was in production but rapidly becoming obsolete as a tank. It was also one of the few chassis that could accommodate such a large gun.citation needed In separate devleopment were tank designs using the 17 pdr - this would lead to the Cruiser Tank, Challenger2 and the Sherman Firefly.
The Valentine had a relatively small hull and it was not possible to use a turret. Instead the gun was mounted in a simple low open-topped armoured box with gun barrel to the rear. This kept the overall length of the Archer short. However, this meant that on firing the gun breech recoiled into the driver's space.
The rear mounting at first seemed like a liability, but it was soon made into an advantage. Combined with its low silhouette, the Archer made an excellent ambush weapon, allowing its crew to fire off a few shots, then drive away without wasting time turning around.
Service
Production started in mid 1943 and the Archer began to be issued in October 1944, and saw combat in the Western Front and the Italian Campaign. By the end of the war, 655 of them had been produced. The Archer was classified as a self-propelled gun and as such was operated by the Royal Artillery (RA) rather than a Cavalry or British Tank Regiment. The 3in SP, Wolverine and related 17pdr SP. Achilles in British service was also operated by RA units.
