The first major technological development, Bugatti's re-introduction of mid-engined cars (following Ferdinand Porsche's pioneering Auto Unions of the 1930s), occurred with the Type 251, which was unsuccessful. Australian Jack Brabham, world champion during , , and , soon proved the mid-engined design's superiority. By , all regular competitors had switched to mid-engined cars. The Ferguson P99, a four-wheel drive design, was the last front-engined F1 car to enter a world championship race. It was entered in the 1961 British Grand Prix, the only front-engined car to compete that year.