Gianclaudio Giuseppe "Clay" Regazzoni (5 September 1939 – 15 December 2006) was a Swiss racing driver. He competed in Formula One races from 1970 to 1980, winning five Grands Prix. His first win was the Italian Grand Prix at Monza in his debut season, driving for Ferrari. He remained with the Italian team until . After a single season with BRM, Regazzoni returned to Ferrari for a further three years, to . After finally leaving Ferrari at the end of 1976, Regazzoni joined the Ensign and Shadow teams, before moving to Williams in , where he took the British team's first ever Grand Prix victory, the 1979 British Grand Prix at Silverstone.