|Tank, Heavy, TOG I|
|Place of origin||United Kingdom|
|Manufacturer||William Foster and Co. Ltd.|
|Weight||80 long tons (90 short tons; 81 t)|
|Length||10.1 m (33 ft 2 in)|
|Width||3.1 m (10 ft 2 in)|
|Height||3 m (9 ft 10 in)|
|Crew||8 (commander, gunner, loader, driver, 4x sponson gunners)|
|Armour||62 mm (2.4 in)|
|QF 2 pdr|
|2.95 inch (75 mm) howitzer|
|Engine||Paxman diesel 12TP driving English Electric generator
600 hp 
|Transmission||English Electric motors|
|Speed||14 km/h (8.7 mph)|
The Tank, Heavy, TOG 1 was a prototype British heavy tank 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 successful performance of another cross country design, the Churchill tank, and the mobile war that was being fought.
In July 1939 the Special Vehicle Development Committee was drawn up for future tank designs suitable for Great War conditions under Sir Albert Stern; who had been on the original Landships Committee and head of the Tank Supply Depot during World War I. The committee included others who had been instrumental in the development of the tank during the Great War: former Director of Naval Construction, Sir Eustace Tennyson d'Eyncourt, General Ernest Swinton, engine designer Harry Ricardo, the gearbox and transmission expert Major Walter Gordon Wilson. Unsurprisingly they got the nickname "The Old Gang" and the initials TOG were applied to their designs.
Together they proposed the development of a heavy tank design, which they entrusted to another of the first tank's developers and builders of the first tank, Sir William Tritton of Foster's of Lincoln.
Their specification was comprehensive. As well as being able to operate across ground broken up by shelling and waterlogged, it was expected to resist 47-mm anti-tank guns and 105-mm field guns or howitzers at 100 yd (91 m). Main armament would be a field gun mounted in the front - effective against 7 ft (2.1 m) thick reinforced concrete - and two 2-pounder guns, the latter in sponsons. For use against infantry there would be a machine gun firing forward, one in each sponson, and one firing to the rear. To provide cover four 2-inch smoke mortars were included.
Design work by Fosters began in February 1940. Designed with trench crossing abilities to the fore and the capability to carry infantry as well, the design as built was a large hull with side doors supported on broad tracks, with a small Matilda II turret on top.
It was realised that the track drive running over the hull was not necessary and work began on a follow-up design in June 1940. The prototype TOG I was delivered in October 1940. After problems with the electro-mechanical drive, it was converted to hydraulic drive designed by Fluidrive Engineering, 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.
- White BT, British Tanks 1915-1945 Ian Allen Publishing, London
- David Fletcher The Great Tank Scandal - British Armour in the Second World War, Part 1 HMSO (1989) ISBN 0 11 290460 2).