At the British War Office, there was a long-felt need for an upgunned version of the Valentine, but the narrow hull of the tank did put severe constraints on the size of the turret.
To install a bigger gun. the L/52 6-pounder [57mm] instead of a 2-pounder [40mm], to the Valentine III/V 3-men tower, it was necessary to leave the third crew member out of the turret, to give up the coaxial Besa MG along with the 2" internally loaded bomb thrower (now installed outside the turret), and to decrease the side armor from 60 to 43mm.
Production at Vickers-Armstrongs Ltd. at Newscastle started in December 1941 and the new model entered service in 1942 and was the first to be able to compete against the last German Panzer III, as far as firepower was concerned.
The Russian who always estimated the Valentine for its reliability and performance liked the new »Valentine IX« very well as it was the sort of straightforward but effective design that was likely to appeal to Soviet tank crews.
The Soviet Government Purchasing Commission in the U.S.A. wrote in August 1942, particularly asking for the number of Valentines shipped to the U.S.S.R. to be increased because "these tanks have given a fine performance in combat action."
Thus, production otherwise having seized in 1943 continued for the single purpose of fulfilling the demands of the Eastern ally who mainly deployed the tank to the reconaissance units of the southern fronts.