The Valentine Archer Self Propelled gun was designed and manufactured by Vickers-Armstrong’s and was based on the Valentine tank chassis, although small it was able to cope with the weight of the 17 pounder gun. This was one of the few allied guns that could penetrate the armour of the Tiger tank. Up until this point in the war the 17 pound gun had to be towed by a vehicle across the battlefield, this and getting it into position without being seen had it’s disadvantages, making it more effective as a defence weapon rather than being used in the attack.The Valentine Archer Self Propelled gun was just under 22 feet long and 9 feet wide weighting 15 tons and had a top speed of 20 mph. It had a crew of four and also carried a .303 Bren machine gun. It was powered by a 6-cylinder two-stroke Detroit Diesel 71 Series engine producing just over 190 bhp which produced more power than the engine fitted to the standard Valentine tank. The prototype was tested in April 43 with production starting soon after, the first vehicles entered service in October 44 and was operated by the Royal Artillery. The unusual thing about the Archer Self Propelled gun was that the 17 pounder gun was rear mounted. The long barrel stretched over the engine compartment, this helped keep the overall length of the vehicle down, another advantage to this layout was that it made it a very good ambush vehicle. The Archer could lay in hiding from the approaching enemy, fire its gun and then drive away without having to turn around with the risk of being seen. One disadvantage with this layout was, that when the gun was fired it recoiled into the driver’s space making it advisable for the driver to leave his seat before the gun was fired.A total of 655 Valentine Archer Self Propelled guns were manufactured between 1943 and 1945. After the war some of the Archer,s were used in the British Army of the Rhine, and some were sold to the Egyptian Army.