The tank was invented by the British in 1916 and first used during World War I, with nearly simultaneous development in France. Tanks of the First World War reflected the novelty of the idea and the primitive state of the automotive industry. World War I tanks moved at a walking pace, were relatively unreliable, and the best usage of them was still developing up to the war's end. A breakthrough in tank design was the Christie suspension: a suspension system developed by American engineer J. Walter Christie which allowed considerably longer movement of the suspension than conventional leaf-spring systems then in common use, and allowed the tanks to have considerably greater cross-country speed.