Johnson’s No. 1 Tropical Tank, one of four experimental vehicles built at the Woolwich Arsenal under instructions from the Master General of Ordnance to limit the use of experimental features as much as possible. Thus although it also used wire-rope suspension the tracks were much more conventional with only a limited amount of lateral ﬂexibility. It was powered by a four-cylinder Tylor engine rated at 45hp (eﬀectively a London bus engine) and like the Light Infantry Tank used a four-speed gearbox and Rackham clutches for steering. Weighing less than six tons it was certainly light and thinly armoured, but probably suitable for fghting on the Indian Frontier against tribesmen armed with ancient muskets. It was an untidy-looking design, with a driver’s cab at the front, alongside the engine, and two machine-gun turrets further back, the one on the right-hand side leading with that on the left behind it. No weapons were ever ftted, but the apertures look large enough to take a Vickers or Lewis gun. Te air-cooled Hotchkiss was never used in India, which seems to have been the most likely destination for this tank, although it never went there. In fact, having gone to the Tank Testing Section in November 1921 it was returned to Woolwich Arsenal in October 1922 and was never heard of again. Te other vehicles in the series were a supply carrier and gun transporter along with an amphibian of unknown appearance, but they were not tanks.
This is the unique Supply Tank built on the chassis from Philip Johnson’s Tropical Tank of 1921 service history is unknown.