Thomas Chatterton Williams: Race, identity and power

Not just in the United States, but across the world the Black Lives Matter movement has prompted debate about race, identity and power. It is a campaign predicated on ideas about what it means to be black and white; but what if those very terms are themselves part of the problem? Stephen Sackur speaks to Thomas Chatterton Williams, a mixed-race American writer and self-declared ex-black man, whose ideas present a challenge to so-called 'woke' culture. How much room is there right now for respectful, thoughtful debate?