Guests on today's Christmas edition of the children's entertainment show include chart-topping pop group Spice Girls, Childline campaigner Esther Rantzen. and actor Sebastian Goldspink-alias Charlie Byrd from Heartbreak High. Bobby Davro and Peter Simon return with plenty of festive fun and games in Run the Risk, Trev and Simon embark on a seasonal Transmission Impossible, and the Leprechauns are busy hanging up their stockings. With Zoe Ball and Jamie Theakston.