Yuval Noah Harari, the author of Sapiens and Homo Deus, explores the long history of inequality – from the Stone Age onwards – and asks whether we are on the brink of creating a huge “economically useless” underclass, unable to keep up with enhanced humans, the owners of increasingly valuable data and, eventually, artificial intelligence. Presenter: Ruth Alexander Producer: Estelle Doyle Editor: Richard Knight (Photo: Yuval Noah Harari, Credit: Daniel Thomas Smith)