Should anything be off limits in comedy? It's meant to be subversive. It finds laughter in dark and difficult places, but when comedy goes wrong things can get ugly. Stephen Sackur speaks to Kathy Griffin, an American stand-up comedian probably best known for being pictured last May holding President Trump's severed head in her hand. The Trump head was fake, but the outrage was real - from the President, the TV network which fired her, the FBI which investigated her and the public which heaped abuse on her. What was - and is - Kathy Griffin thinking?(Photo: Kathy Griffin at a press conference at The Bloom Firm, 2017. Credit: Frederick M. Brown/Getty Images)