The third 6-part radio series, The Hitchhiker's Guide to the Galaxy: Tertiary Phase, based on Life, the Universe and Everything, ran on BBC Radio 4 from Tuesday September 21 to October 26, 2004, with repeats on the following Thursdays.

Broadcast on BBC Radio 4, 21 September 2004 - 26 October 2004

Cast:

    * The Book: William Franklyn
    * Arthur Dent: Simon Jones
    * Ford Prefect (and Hactar, in flashbacks, uncredited): Geoffrey McGivern
    * Zaphod Beeblebrox: Mark Wing-Davey
    * Trillian: Susan Sheridan
    * Marvin the Paranoid Android: Stephen Moore
    * Elder of Krikkit: Dominic Hawksley
    * Slartibartfast: Richard Griffiths
    * Eddie the Computer: Roger Gregg
    * Krikkit Civilian: Bob Golding
    * Wowbagger: Toby Longworth
    * Henry Blofeld: Himself
    * Fred Trueman: Himself
    * Prak: Chris Langham
    * Hactar: Leslie Phillips
    * Announcer: John Marsh
    * Krikkit Commander: Dominic Hawksley
    * Dispatcher (and Silastic Armorfiends, uncredited): Bob Golding
    * Krikkit Man One (and Mancunian Correcting-Fluid Magnate, uncredited): Michael Fenton Stevens
    * Krikkit Man Two (and Krikkit song by): Philip Pope
    * Krikkit Man Three: Tom Maggs
    * Thor: Dominic Hawksley
    * Agrajag: Douglas Adams
    * Award winner: Bob Golding
    * Woman with the Sydney Opera House Head: Joanna Lumley
    * Party Doorman: Paul Wickens
    * Wikkit Voice: Dominic Hawksley
    * Judiciary Pag: Rupert Degas
    * Henry Blofeld: Himself
    * Fred Trueman: Himself
    * Krikkit Robots: Dominic Hawksley
    * Zem the Mattress: Andy Taylor
    * Walkie Talkie: Fiona Carew
    * The Boy: Theo Maggs
    * Deodat: Bruce Hyman


Wikipedia: http://en.wikipedia.org/wiki/Tertiary_Phase#The_Tertiary_Phase