Vickers was among several companies approached in 1938 to build the Infantry Tank Mk II in conjunction with Vulcan. Instead, they were able to propose a new infantry tank. The plans for the new tank were submitted in February 1938. It wasn't until 1939 that the production order for what was to known as the Infantry Tank Mk III, Valentine, was placed. The first production vehicle was released to the British Army for trials purposes in May 1940 where it was found to be mechanically reliable and good gun platform. The first production tanks entered service in late 1940 and first saw action in North Africa in June 1941. 8,275 Valentines had been produced by the time production ended in 1944. Of those 8,275, 1,420 were built in Canada with all but 30 of them being shipped to the Soviet Union under Lend-Lease.

The Valentine was built in twelve different marks that varied based on armament, number of crew members and engine type. The earliest ones were produced with a QF 2-pounder as the main armament and an AEC gasoline engine. Later marks had GMC diesel engines and either a QF 6-pounder (57-mm) or a 75-mm main gun. The Valentine was used in North Africa, Europe and in the Pacific.