 In 1948, Cox was the British six mile (10 km) champion, with a time of approximately 29 minutes.In the Men's 10,000 metres competition, he did not receive a medal, placing 7th.He later claimed that he was told by 1924 Olympian Harold Abrahams that he had run an extra lap due to confusion caused by Emil Zátopek, and should have placed 5th instead.