Doctor Who: The Ark in Space (Part 4)

"The Ark in Space (Part 4)" is the eighth episode of season twelfth of the British science fiction television series Doctor Who and the 359th episode of the series overall. It is the fourth and final installment in "The Time Warrior" serial. It was directed by Alan Bromly and written by Robert Holmes. It was produced by Barry Letts and first aired on BBC One on February 15th, 1975.