I'm Sorry I Haven't a Clue is the most listened to comedy programme on British radio. It regularly attracts an audience of 2.5 million listeners on Radio 4, a figure that would put it comfortably into the top ten programmes on BBC2 or Channel 4.

The format of the game is very simple: four players - Graeme Garden, Tim Brooke Taylor, Barry Cryer and a guest are given silly things to do by the Chairman Jack Dee, with Colin Sell setting some of them to music.

Clue continues to enjoy a long and successful run on BBC Radio 4, and in 2007 the show took on a new life with the first of many national tours, playing to 2500-seat theatres across the country.

With the 40th anniversary this autumn, the world of Clue continues to expand and evolve, constantly creating new games and welcoming a new generation of Clue players, attracting new fans along the way.