Tom Robinson tells the story of the so-called suicide song "Gloomy Sunday". In the 1930s and 40s it was worldwide hit recorded by Paul Robeson, Billie Holiday and many others. But its melancholy lyrics and haunting melody led to lurid reports that dozens of listeners had been influenced to take their own lives, and a scandal ensued. The record was considered so dangerous that the BBC banned certain versions. But famous singers and musicians, right up to the present day, keep on performing and recording it. Could a song be this powerful? Tom Robinson investigates.