I'm Sorry I Haven't a Clue down opportunities to work on it as he preferred to remain a listener. The official, authorised history of the show and ISIRTA, "The Clue Bible" by Jem Roberts, was published by Preface Publishing in October 2009. Humphrey Lyttelton, primarily known as a jazz trumpeter and bandleader, was invited to be chairman because of the role played by improvisation in both comedy and jazz music. In the first series Lyttelton shared the role of chairman with Barry Cryer but he made it his own (especially once Cryer replaced Cleese as a regular panellist) and continued as chairman until his death on
I'm Sorry, I'll Read That Again It also may have influenced other spoof-based British radio programmes such as "Radio Active", "On the Hour", "The Sunday Format", "The News Huddlines", and later "Bleak Expectations". Several cast members have since appeared in the radio comedy panel game "I'm Sorry I Haven't a Clue", a spinoff from "ISIRTA" that has outlived it by decades. Tim Brooke-Taylor and Graeme Garden continue as regulars on the show. Episodes of "ISIRTA" have frequently been heard on BBC Radio 4 Extra (available on digital television, DAB digital radio and the web). Listeners in Australia occasionally find "ISIRTA" in the 5.30am vintage comedy timeslot