Season 18

The eighteenth season of Doctor Who ran between 30 August 1980 and 21 March 1981. It was Tom Baker's final season. It was also the first season of John Nathan-Turner's producership. Many of the changes he brought in during this season would continue throughout the 1980s — some to the end of Doctor Who's original run. Amongst the more obvious changes during the season were: a new logo, a reworking of the theme tune, fully electronic incidental music, a raft of new writers and directors, a new maroon-coloured outfit for the Doctor and the introduction of the question mark motif on the Doctor's clothing. Finally, it was Barry Letts' swansong on the programme. He had returned for this one year to executive produce.

Overview
Season 18 consisted of seven stories and twenty-eight episodes. It was the last season of the original series to have an autumn-to-spring broadcast schedule and the last to have an autumn start until Season 23. After this season, the number of episodes per season began to decline, after a relatively stable episode count for the whole of the 1970s.

From Full Circle onwards, the season featured a story arc involving E-Space and the return of the Master. The stories were darker and more adult in tone than those during the Graham Williams era. They also attempted to emphasise science, much to the satisfaction of both script editor Christopher H. Bidmead and executive producer Barry Letts. (REF: The Fourth Doctor Handbook)

Notably, this season revolves around the theme of entropy, linking together all of its stories in a rare phenomenon for the show (while other story arcs would be linked together via people, objects, etc, the use of an overarching theme for a season was unprecedented). This theme would eventually foreshadow and culminate in the Doctor's regeneration at the end of the season.

From a ratings standpoint, it sits right at the very nadir of Doctor Who history. It is easily the worst-ranked season of Doctor Who, with 17 of its 28 episodes outside of the top 100 shows. Indeed, the 9 lowest-charting episodes in Doctor Who history come from this season. Full Circle's second episode remains the worst-charting episode of Doctor Who. Its paltry 3.70 million viewers were only good enough for what was, even by the season's low standard, an extremely anaemic 170th place during the week of 1 November 1980. In terms of pure ratings, as opposed to ranking, it was not quite the worst of the lot, with all four seasons after the 1985-86 hiatus faring worse in this regard. But it was easily the least-watched Tom Baker season, with an average of only 5.8 million Britons watching each episode. (REF: The Fourth Doctor Handbook) The decline in ratings has been attributed to direct competition from ITV. The first half of the season was up against, an American import with considerably better production values. (INFO: Full Circle)

Recurring

 * The Fourth Doctor - Tom Baker
 * Romana II - Lalla Ward
 * K9 (voice) - John Leeson
 * Adric - Matthew Waterhouse
 * Nyssa - Sarah Sutton
 * Tegan Jovanka - Janet Fielding
 * - Anthony Ainley
 * The Fifth Doctor - Peter Davison

Stories set during this season

 * AUDIO: The Invasion of E-Space (between State of Decay and Warriors' Gate)
 * PROSE: O, Darkness (between State of Decay and Warriors' Gate)
 * Involvement in PROSE: The Eight Doctors (after State of Decay)
 * PROSE: Mauritz (between The Keeper of Traken and Logopolis)

VHS

 * The Leisure Hive (contians The Leisure Hive)
 * Meglos (contains Meglos)
 * The E-Space Trilogy (contains Full Circle, State of Decay and Warriors' Gate)
 * The Keeper of Traken (contains The Keeper of Traken)
 * Logopolis (contains Logopolis)
 * The Tom Baker Years (contains all the stories)

DVDs
All serials of season 18 were released individually between 2004 and 2011.

Novels

 * Doctor Who and the Leisure Hive
 * Meglos
 * Full Circle
 * Doctor Who and the State of Decay
 * Doctor Who and Warriors' Gate
 * Doctor Who and the Keeper of Traken
 * Logopolis