The Medium Mark A Whippet was a British tank of the First World War. It was intended to complement the slower British heavy tanks by using its relative mobility and speed in exploiting any break in the enemy lines. Development and production history On 3 October 1916 William Tritton, about to be knighted for developing the Mark I, proposed to the Tank Supply Committee that a faster and cheaper tank, equipped with two engines like the Flying Elephant, should be built to exploit gaps that the heavier but slow tanks made, an idea that up till then had been largely neglected. This was accepted on 10 November and approved by the War Office on 25 November. At that time the name for the project was the Tritton Chaser. Traditionally, the name Whippet (after the fast-running dog breed) is attributed to Sir William himself. Actual construction started on 21 December. The first prototype, with a revolving turret taken from an Austin armoured car — the first for a British tank design, as Little Willie's original turret was fixed — was ready on 3 February 1917 and participated (probably without one) in the tank trials day at Oldbury on 3 March. The next day, in a meeting with the French to coordinate allied tank production, the Commander-in-Chief of the British forces Field Marshal Haig ordered the manufacture of two hundred vehicles, the first to be ready on 31 July. Although he was acting beyond his authority, as usual, his decisions were confirmed in June 1917. The first production tanks left the factory in October and two were delivered to the first unit to use them, F Battalion of the Tank Corps (later 6th Battalion), on 14 December 1917. In December 1917 the order was increased from 200 to 385 but this was later cancelled in favour of more advanced designs, the Medium Mark B, Medium Mark C and Medium Mark D. Description This armoured fighting vehicle was intended for fast mobile assaults. Although the track design appears more "modern" than the British Tanks Mark I to V, it was directly derived from Little Willie, the first tank prototype (itself directly taken from the track design of the Holt tractor), and was unsprung. The crew compartment was a fixed, polygonal turret at the rear of the vehicle, and two engines of the type used in contemporary double-decker buses were in a forward compartment,