Jonathan Dimbleby looks back on half a centenary of the BBC's annual lectures, inspired by his broadcaster father Richard – the ‘voice of the nation'. Since 1972, leading figures from the arts, sciences, judiciary, politics, broadcasting, the forces and even the royal family have delivered speeches that have always been provocative, challenging and at the cutting edge of their particular field.Jonathan looks through a personal selection of programmes and explores how thoughts expressed decades ago can still resonate today. Amongst the speakers featured in this collection are President Bill Clinton, Jeanette Winterson, Terry Pratchett, Bill Gates, Tim Berners-Lee, Stella Rimington and King Charles III.