David Mitchell, Roisin Conaty, Phill Jupitus

Jimmy Carr hosts the comedy panel show's version of the famous quiz, with team captains Sean Lock and Jon Richardson joined by guests Jonathan Ross and Roisin Conaty. Countdown regular Susie Dent is in Dictionary Corner with David O'Doherty, while maths whizz Rachel Riley provides the letters and numbers with a little 'help' from Joe Wilkinson.