The Medium Mark B was the result of Sir William Tritton, one of the designers of the Mark I, not including the other lead designer, Lt. Walter Wilson, in the development of the Medium Mark A. When it was felt that the Mark A was underpowered, Wilson, now a Major, began developing a replacement, the Medium Mark B. Unfortunately, due to the fact that the prototype wasn't completed until September 1918, it never had serious production - only 102 were built, and only 45 of those entered service.
