engine stopped, and the car was retired. In 1973 Purley hired a March and with backing from his family's refrigeration company he made an attempt at Formula One. At the 1973 Dutch Grand Prix, upon witnessing a crash which left fellow British driver Roger Williamson trapped in his overturned and burning car, Purley abandoned his own race and attempted to save Williamson, who was participating in only his second Formula One race. Purley later recalled that upon arriving at the scene, he heard Williamson crying for help as the fire began to take hold. Purley's efforts to right the car and extinguish the flames were in vain as he received no help from nearby track marshals or emergency workers, in spite of attempts to encourage them, and other passing drivers, to come to his aid; Williamson died from asphyxiation. The marshals were not wearing fire resistant clothing and the passing drivers assumed that Purley was attempting to extinguish his own car, having escaped a fiery crash unharmed. A sequence of pictures taken by photographer Cor Mooij of the accident won the Photo Sequences category of that year's World Press Photo. Later, Purley was awarded the George Medal for his rescue attempt. The story, and film footage of the rescue attempt, feature in a 2010 BBC documentary titled Grand Prix: The Killer Years. Apart from a one-off participation with Token at his home Grand Prix in 1974, Purley stayed out of Formula One for a few years, preferring to compete in Formula Two driving Chevrons and Marches for Hong Kong-based millionaire Bob Harper, and Formula 5000 where he won the British Championship in 1976 in a Chevron powered by the Cosworth GA 3.4-litre V6 engine. In 1974 Purley won the Brighton Speed Trials driving a Trojan-Chevrolet T101, winning again the following year in a Chevron-GA B30. He returned to Formula One in 1977 with his own LEC chassis designed by Mike Pilbeam and run by Mike Earle. It was this car in which he suffered serious injuries in an accident during practice for that year's British Grand Prix. He survived an estimated 179.8 g when he decelerated from 108 mph (173 km/h) to 0 in a distance of 26 inches (66 cm) after his throttle became stuck wide open and he hit a wall. This was the highest measured g-force ever survived by a human being until 2003 (when Kenny Bräck's