Summary: Jimmy Carr hosts the first of three new comedy editions of the famous quiz. Team captains Sean Lock and Jon Richardson are joined by Peep Show star David Mitchell and stand-up comedienne Roisin Conaty. Phill Jupitus is in Dictionary Corner with Susie Dent, while Joe Wilkinson `helps' Rachel Riley with the letters and numbers.

Summary: Jimmy Carr hosts the comedy panel show's version of the famous quiz, with team captains Sean Lock and Jon Richardson joined by guests David Baddiel and Trevor Noah. Countdown regular Susie Dent is in Dictionary Corner with Joey Essex, while maths expert Rachel Riley provides the letters and numbers with help from Alex Horne and the Horne Section.

Summary: Jimmy Carr hosts the comedy panel show's version of the famous quiz, with team captains Sean Lock and Jon Richardson joined by guests Vic Reeves and Jo Brand. Countdown regular Susie Dent is in Dictionary Corner with Adam Buxton, maths expert Rachel Riley looks after the letters and numbers, and there's a special appearance by Rob Beckett.

Summary: Jimmy Carr hosts, alongside Sean Lock and Jon Richardson, who are joined by Jason Manford and Stephen Mangan. Tim Key joins Susie Dent in Dictionary Corner, while Joe Wilkinson 'helps' Rachel Riley.

Summary: Jimmy Carr hosts, alongside team captains Sean Lock and Jon Richardson, who are joined by Jo Brand and Claudia Winkleman. Bill Bailey joins Susie Dent in Dictionary Corner.

Summary: Jimmy Carr hosts, alongside team captains Sean Lock and Jon Richardson, who are joined by Bill Bailey and Josh Widdicombe. Jake Yapp joins Susie Dent in Dictionary Corner.