Luol Deng is the multi-millionaire face of the Chicago Bulls, and one of President Obama's favourite sports stars. But that is only part of his extraordinary story. He is the star of the Team GB basketball team, courtesy of the British passport which he was given after he and his family fled the civil war in southern Sudan. That was twenty years ago. In the latest of our World Olympics Dreams series Tim Franks traveled with Luol Deng as he made his first, emotional return to his home country.