After the failure of Pedrail's Lanship and due to a need for better track units, the Landship Committee turned to America's tractors and soon began experiments with the small Killen-Strait, which utilized a tri-wheeled arrangement with three individual steel track units with wooden shoes.
Lloyd George and Winston Churchill were very impressed with the Killen-Strait after been shown, in 1915, how it could easily overcome obstacles, such as piles of railroad sleepers, trench obstacles and barbed wire.
Initially the Killen-Strait was only ever brought to England to demonstrate its superior tracks and their abilities, and was never intended to be used as a vehicle of war in itself. However, the committee was so impressed with the little machine that they fitted her out with the body of a Delaunay-Belville armored car to show everyone how strong a converted tractor could be.
Because of this we find that the little Killen-Strait tractor from America inadvertently found itself recreated as the world's first tracked armored vehicle.