After covering weighty issues like death, love, religion and spam javelins, the 'King of Edinburgh' (6 Music) is in a frivolous mood with this show about daftness, whether the term cool comedian is an oxymoron, bouncing joyously on the sofa and how Herring's whole career is a failed attempt to top a piece of visual slapstick comedy he came up with at 16. Can he revisit the joke thirty years on, or will it smash his old bones?