Raoul Peck on photographer Ernest Cole, the death of Bill Dare, 14th-century art in Siena, Colum McCann's novel Twist

A new exhibition at London's National Gallery hopes to shed light on artists in 14th Century Siena, who have often been overshadowed by their Tuscan neighbours in Florence. Samira is joined in the studio by one of the curators, Imogen Tedbury, and by Maya Corry, a Renaissance expert from Oxford Brookes University to discuss the astonishing colours and use of gold by artists like Duccio, the Lorenzetti brothers and Simone Martini. The death has been announced of Bill Dare, the creator of Radio 4's The Now Show and Dead Ringers. He nurtured new writers and performers including David Baddiel, Rob Newman, Hugh Dennis and Steve Punt, of The Mary Whitehouse Experience as well as the comedian Jon Holmes, who explains how they first met. Haitian filmmaker Raoul Peck, best-known for his Oscar and BAFTA nominated documentary about James Baldwin 'I Am Not Your Negro', discusses his latest film 'Ernest Cole: Lost and Found', about the brief life of a young South African photographer who had to flee his homeland in 1968 to publish his book of photos which exposed the horrors of apartheid to the world.The Booker and Oscar-nominated writer Colum McCann discusses his thrilling new novel Twist, a dive in to the dark depths of the modern human condition set on board a ship repairing the fragile cables which connect us on the ocean floor. Presenter: Samira Ahmed Producer: Claire Bartleet