From 1940, new tank designs were prepared. The Battle of France had shown the importance of medium tanks. The British Army sought to have the US manufacture British designs, but the US refused, offering instead to share the output of US factories building US designs. The United States Army had a requirement for a medium tank with a 75 mm gun, and developed the M3 Medium Tank as an interim design. The medium M3 tank was intended to quickly get a 75 mm gun into the field, pending the design of a tank with a 75 mm gun in a fully rotating turret. The British immediately ordered the M3 Medium Tank for their own use as the 'Lee', and some with modifications to their requirements as the 'Grant' (most obviously carrying a different turret).