LEC racing returned to Formula One in 1977 with their own LEC chassis designed by Mike Pilbeam and run by Mike Earle. It was this car in which Purley suffered serious injuries in an accident during pre-qualifying for that year's British Grand Prix. He survived an estimated 179.8 g when he decelerated from 173 km/h (108 mph) to 0 in a distance of 66 cm (26 inches) after his throttle got stuck wide open and he hit a wall. For many years, this was thought to be the highest g-force ever survived by a human being. He suffered multiple fractures to his legs, pelvis and ribs.