Regular Cast: Nicholas Young as John, Elizabeth Adare as Liz, Peter Vaughan-Clarke as Stephen, Philip Gilbert as TIM, Christopher Chittell as Chris.

Also Starring: Nigel Pegram as Grandfather, Jason Kemp as Robert, Simon Merrick as Police Inspector, Ray Burdis as Johnson.

Also Starring: Sylvia Coleridge as Professor Sylvia Garner, Stanley Lebor as Gaius, Leonard Pieroni as Lothar, Brian Stanion as Professor Cawston, Sammie Winmill as Carol, Stephen Jack as Zenon, Mike Lee Lane as Guthron, Peter Duncan as Cotus, Leonard Gregory as Trystan.

Also Starring: William Relton as Douglas McLelland, Lindsay Campbell as Lt. General McLelland, Eric Young as Lee Wan, Simon Gipps-Kent as Paul, Derek Murkott as Major Longford, Arnold Peters as Dr. Laird, Nigel Pegram as Traffic Warden, Bill Treacher as Doomsday Man .