During the long history of the British science fiction television programme Doctor Who, a number of stories were proposed but, for a variety of reasons, never fully produced. Below is a list of unmade serials which were submitted by recognised professional writers and the BBC had intended to produce, but for one reason or another were not made. Many have since been the subject of a feature in Doctor Who Magazine, or other professional periodicals or books devoted to the television show.
Such serials exist during the tenure of each of the previous eleven incarnations of the Doctor. The reasons for the serials being incomplete include strike action (which caused the partially filmed Shada to be abandoned), actors leaving roles (The Final Game, which was cancelled after Roger Delgado's death), and the series being put on hiatus twice—once in 1985, and again in 1989—causing the serials planned for the following series to be shelved.
The plots of the unmade serials also vary. A theme of a civilisation where women are dominant was proposed twice—once for The Hidden Planet, and again for The Prison in Space. In some cases, elements of unmade serials were adapted, or were moved from one serial to another; for example, Song of the Space Whale was intended to be the introduction of Vislor Turlough until it was repeatedly set back, causing Mawdryn Undead to be Turlough's first appearance.
Some unused stories have since been adapted for other media. Shada was made into an audio play of the same name, while several unmade serials have been compiled into an audio series released by Big Finish called The Lost Stories.
The first serial of the series was originally to be written by C. E. Webber, and would concern the four main characters (at that point named as the Doctor, Cliff, Lola, and Biddy) being shrunk to a "miniature size" and attacked by giant animals. The episode would have revealed that the Doctor had escaped from "his own galaxy" in the year 5733, seeking a perfect society in the past, and that he was pursued by agents from his own time who sought to prevent him from stopping their society from coming into being. The story was rejected in June 1963 on the grounds that the story was too thin on characterisation and that the giant monsters would be clichéd and too expensive to produce. Much of the setup was retained for An Unearthly Child, though the details about the Doctor's home were removed. The story's premise was reused for a submission by Robert Gould, The Miniscules, which was planned to be the fourth serial, but this story was dropped in January 1964.