UFO (TV series)
Following poor ratings for "Joe 90" (1968–69) and the cancellation of children's espionage television series "The Secret Service" (1969) after only one series, Lew Grade approached Gerry Anderson to look into creating his first live-action TV series. Anderson worked with his wife, Sylvia, and producer Reg Hill to create a sci-fi adventure series based around UFOs. Anderson said the core idea for the series was that UFO sightings were a common issue during the late 1960s and that idea of aliens harvesting human organs came from the work of Christian Barnard and his pioneering transplant operations. The creative team initially envisioned an organisation called UFoeDO (Unidentified Foe Defence Organisation), which was to become the secret SHADO (Supreme Headquarters Alien Defence Organisation).
UFO (TV series)
Principal photography commenced in April 1969 with production based at MGM-British Studios in Borehamwood. Seventeen episodes were filmed at these studios before they closed at the end of 1969. Production resumed at Pinewood Studios when studio space became available in June 1970, leading to an unusual seventeen-month long production before the final nine episodes were completed. The delay in production saw both George Sewell (who played Alec Freeman) and Gabrielle Drake (Lt. Gay Ellis) both drop from the cast as they were no longer available.