Red Light, Green Light. Joan Bakewell asks whether the world's oldest profession should be treated as a business like any other. Lindi St Clair believes it should and has started a political party aimed at achieving it. But for many others prostitution is immoral. They argue that the law has a duty to protect people from themselves and society from prostitution. Heart of the Matter examines both sides of this age-old dispute. Producer Krishna Govender Series producer Olga Edridge