Harriet Beveridge says we don't take humour seriously enough and thinks it's a "woefully misunderstood and underused tool". She extols its power in managing human relationships, dealing with adversity and overcoming prejudice. "Cracking a joke is a hugely effective way to hold up a mirror, to challenge fixed ideas, because jokes shatter assumptions." Recorded in front of a live audience at Womad, the World of Music, Arts and Dance festival in Wiltshire. Presenter: Mark Coles Producer: Sheila Cook