The German 1000 ton Ratte tank is a pretty well known device, and similar monstrosities described by well-meaning Soviet citizens volunteering their ideas. Turns out, the Western Allies were not immune from these flights of fancy. This suggestion was forwarded by a pretty high ranking official: than Sir Howard d'Egville. The description begins very promisingly: "...this vehicle, while not actually a tank, is of such capacity that it would be equal, in both offensive and defense power, to a considerable number of tanks." The armour is fairly reasonable at 5 inches (127 mm), but the armament is "of great striking power, including 4 inch naval guns". The vehicle would be transported in section, and if a section was knocked out, it would be removed and replaced. While not going into details on the design, d'Egville wanted a mockup built in Canada, and then the parts manufactured in several places, to preserve secrecy.
In reply, he received a rather ruthless evaluation: "it is highly unlikely that there is anything of practical value in the idea".