Dwain Chambers, the fastest man in Europe and one of Britain's main hopes for an Olympic gold medal next year, has tested positive for a new banned designer anabolic steroid and could face a life ban from the sport. Britain also faces being stripped of the 4 x 100m silver medal it won at the world athletics championships in Paris in August as Chambers was part of the team. The 26-year-old Londoner seems certain to miss the games in Athens if he is found guilty of taking tetrahydrogestrinone (THG), which until last week was thought to be undetectable. Sources familiar with the process have told the Guardian that traces of the drug were found in a urine sample that the European 100 metres champion and record-holder provided during an out-of-competition test at his training base in Saarbrucken, Germany, on August 1.