Whippet Mk A

Medium Mk A Whippet
Whippet Firefly of F Battalion in The Museum of the Army in Brussels (original colours)
Type	Medium tank
Place of origin	United Kingdom
Service history
In service	1918-1930s
Production history
Designer	William Tritton
Manufacturer	Fosters of Lincoln
Produced	1917-1918
No. built	200 by 14 March 1919
Specifications
Weight	14 t
Length	6.10 m (20 ft)
Width	2.62 m (8 ft 7 in)
Height	2.75 m (9 ft)
Crew	3
Armour	14 mm
Main armament	4 × 0.303 inch Hotchkiss machine guns
Secondary armament	none
Engine	2× Tylor Twin 4-cylinder side-valve JB4 petrol engine 2x 45 hp (67 kW)
Power/weight	6.4 hp/tonne
Transmission	4 forward speeds and 1 reverse
Suspension	unsprung
Speed	13.4 km/h (8.3 mph)

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. Whippets later took part in several of the British Army's postwar actions, notably in Ireland, North Russia and Manchuria.

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 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.