A first for Great Britain's tank development, actual end users of the tanks were asked in May 1926 to give input on what they would like to see in the next tank. The Royal Tank Corps Center finished their report in July 1926 and the new specifications that were suggested was to add two machine gun turrets, and be transportable by rail. The efficient use of oil was needed as the Mark IIs were known to consume oil at large rates. The fuel tanks should be located outside the hull. Thicker front and belly armor was needed for protection when crossing crests. Vickers-Armstrong was given these specifications for coming up with a new design.
In 1928 Vickers Armstrong designed the Medium Mark III and it was also known as the "16 tonner".
Development was stopped in 1931 after a financial crisis cut defense spending.