The Comet was the best British tank of WW2. Its 77mm gun fired the same ammunition as the 17 pounder gun from a shell case based on the British WW1 anti aircraft gun. The reduction in velocity did not have a too negative affect on the APDS shot and the Comet could still take on a Tiger or Panther at range.
The British Mark V tank was an upgraded version of the Mark IV tank, deployed in 1918 and used in action in the closing months of World War I, in the Allied intervention in the Russian Civil War on the White Russian side, and by the Red Army. Thanks to Walter Wilson's epicyclic gear steering system, it was the first British heavy tank that required only one man to steer it
T26E1 heavy tank 'Super Pershing' with upgraded L73 90mm T15 gun, Europe, 1945. The 90-mm M3 gun of the Super Pershing was similar to the German 88 mm KwK 36 used on the Tiger I. In an effort to match the firepower of the Tiger II's more powerful 88 mm KwK43, the T15E1 90 mm gun was developed and mounted in a T26E1 in January 1945. The end of the war five months later interrupted further development.