Brian Hayes traces the 50-year history of the radio phone-in programme, using archive of its most electric, poignant and confrontational moments. Among the extracts are Britain's first phone-in programme, What Are They Up to Now?, and the late Sir Robin Day trying fruitlessly to defend Margaret Thatcher from an insistent caller who would not let her get a word in. With contributions from some of the phone-in's most important early pioneers. Producer Matthew Dodd