Jimmy Carr returns with Sean Lock and Jon Richardson, who are joined by Jonathan Ross and Roisin Conaty. David O'Doherty joins Susie Dent in Dictionary Corner, and Joe Wilkinson 'helps' Rachel Riley.

Jimmy Carr hosts the words and numbers quiz with Jon Richardson and David Mitchell who take on guest captain Joe Wilkinson and Roisin Conaty. Tom Allen is in Dictionary Corner.

Jimmy Carr hosts as Jon Richardson and Lucy Beaumont take on Roisin Conaty and Joe Wilkinson. Bec Hill joins Susie Dent in Dictionary Corner.

Jimmy Carr hosts as Roisin Conaty and Kiri Pritchard-McLean take on Jon Richardson and Rob Beckett. Comedian Huge Davies is in Dictionary Corner. Regular Countdown mathematician Rachel Riley and lexicographer Susie Dent are on hand to adjudicate

Jimmy Carr hosts, as Roisin Conaty and Asim Chaudhry take on Jon Richardson and Josh Widdicombe. Bill Bailey is in Dictionary Corner. Regular Countdown mathematician Rachel Riley and lexicographer Susie Dent are on hand to adjudicate

Jimmy Carr hosts the words and numbers game show mash-up, with `Countdown' regulars Rachel Riley and Susie Dent. Roisin Conaty and Joe Wilkinson play against Jon Richardson and Nabil Abdulrashid. David O'Doherty is in Dictionary Corner.