The Tank, Heavy, TOG 1 was a prototype British heavy tank design produced in the early part of the Second World War in the expectation that battlefields might end up like those of the First World War and was designed so it could cross churned up countryside and trenches. A single prototype was built but interest faded with the success of the Churchill tank, another cross country performance design, and the mobile war that was being fought.
Designed with trench crossing abilities to the fore and the capability to carry infantry as well, the design was a large hull with side doors supported on broad tracks, with a small turret on top. The prototype TOG I was delivered in October 1940. After problems with the electro-mechanical drive, it was converted to hydraulic drive, a process that took until May 1943 after which it was called TOG 1A. The prototype was sent to Chobham and then seems to have disappeared into history.