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 arrived late in the First World War, at a time when the entire British Army, recovering from the offensives in Flanders, was quite inactive. They first went into action in March 1918, and proved very useful to cover the fighting withdrawal of the infantry divisions recoiling from the German onslaught during the Spring Offensive. Whippets were then assigned to the normal Tank Battalions as extra "X-companies". In one incident near Cachy, a single Whippet company of seven tanks wiped out two entire German infantry battalions caught in the open, killing over 400. That same day, 24 April, one Whippet was destroyed by a German A7V in the world's second tank battle, the only time a Whippet fought an enemy tank.
The Whippet was, a British tank veteran wrote, "the big surprise" of the Royal Tank Corps. Crews used their vehicles' speed to attack troops in the rear. They were so successful that by summer 1918 civilians "seemed to talk in terms of whippets," not knowing of heavy tanks' importance in breaking through fortifications and barbed wire.
After the war, Whippets were sent to Ireland during the Anglo-Irish War as part of the British forces there, serving with 17th Battalion, Royal Tank Corps.