Season 23

Season 23 of Doctor Who ran between 6 September 1986 and 6 December 1986. It starred Colin Baker as the Sixth Doctor. Though produced as four separate serials from a practical standpoint, it aired as a single, connected serial entitled The Trial of a Time Lord. With this season the BBC returned Doctor Who to an autumn season start for the first time since Season 18; this scheduling would remain for the rest of the original series' run.

Overview
This season had a unique format, never again repeated in the show. Doctor Who had returned to production after a near-cancellation and an eighteen month production hiatus. For the first time, a season consisted of a single story, The Trial of a Time Lord, although this was made up of four serials from a production perspective: each serial was written by a different person (save for The Mysterious Planet and the first part of The Ultimate Foe, both of which were written by Robert Holmes) and featured a different story presented as evidence, excluding the final two episodes which concluded the ongoing story of the trial; the trial storyline itself acted as a to bracket the first three serials. As a result, whether The Trial of a Time Lord should be considered one story or four has been intensely debated. This single-story format, sometimes referred to as a "miniseries", would later be utilised for the third and fourth series of Torchwood. In an interview in Doctor Who Magazine 448, Timelash author Glen McCoy said that he came up with the idea of the Doctor being put on trial.

The experiment of forty-five-minute episodes having been deemed a failure, the BBC reverted the series to twenty-five-minute episodes, but kept the episode count at fourteen, effectively halving the number of episodes in a season. The last episode, however, ran thirty minutes. This format lasted for the remainder of the classic series.

This was the final season to feature Colin Baker as the Sixth Doctor; he was fired following its conclusion. He did not return to play the Doctor for the regeneration scene in Time and the Rani, the first story of the following season. It was the last season to use the "neon tubing" logo introduced in 1980. A new arrangement of the Doctor Who theme by Dominic Glynn was introduced this season, but was only used for these fourteen episodes, before being replaced by another new arrangement.

The final serial of Season 23 turned out to be veteran writer Robert Holmes's last contribution to the series, falling gravely ill and passing away before he could finish the script. It was then passed to script editor Eric Saward, who tried to finish the script but got into an argument with producer John Nathan-Turner over its ending. Eventually, Saward gave up and quit working on Doctor Who altogether, withdrawing his contributions to Holmes's script as he left. The script was then passed along to Pip and Jane Baker, who completed it as they saw fit.

Aborted Season 23
Prior to Doctor Who being placed on hiatus after Season 22, a slate of serials of standard length was planned, and scripts were written for several. The decision to recast Season 23 as a single interconnected arc resulted in production of these stories being cancelled.

Three of the stories were subsequently adapted as Target Books novelisations: The Nightmare Fair (which would have seen the return of the Celestial Toymaker), Mission to Magnus (featuring Sil and the Ice Warriors; Sil ultimately appeared in the Mindwarp segment of the Trial of A Time Lord), and The Ultimate Evil. An unofficial audio adaptation of The Nightmare Fair was also produced for charity in 2003.

Beginning in late 2009, Big Finish Productions launched a series of audio dramas covering scripts that had never made it to production, titled The Lost Stories. The first season featured adaptations of The Nightmare Fair, Mission to Magnus, and other story lines planned for the aborted Season 23.

Recurring

 * The Sixth Doctor - Colin Baker
 * The Valeyard - Michael Jayston
 * The Inquisitor - Lynda Bellingham
 * Peri Brown - Nicola Bryant
 * Melanie Bush - Bonnie Langford
 * Sabalom Glitz - Tony Selby
 * Kiv - Christopher Ryan
 * - Anthony Ainley

Guest

 * Katryca - Joan Sims
 * Dibber - Glen Murphy
 * King Yrcanos - Brian Blessed
 * Sil - Nabil Shaban
 * Professor Lasky - Honor Blackman
 * Commodore Travers - Michael Craig
 * Janet - Yolande Palfrey
 * Mr. Popplewick - Geoffrey Hughes

VHS

 * The Trial of a Time Lord (packaged in a tin) (1993)

DVD
All serials of The Trial of a Time Lord were released in a complete box set on 29 September 2008 in region 2, on 7 October 2008 in Region 1, and on 5 January 2009 in Region 4.

Novels

 * The Mysterious Planet
 * Mindwarp
 * Terror of the Vervoids
 * The Ultimate Foe

Stories set during this season
During The Ultimate Foe:
 * Chapters 17-21 of PROSE: The Eight Doctors

Before Terror of the Vervoids from Mel's perspective:
 * PROSE: Business Unusual
 * PROSE: Millennial Rites

Between Terror of the Vervoids and The Ultimate Foe from Mel's perspective:
 * PROSE: The Quantum Archangel
 * PROSE: Instruments of Darkness
 * AUDIO: ''Thicker Than Water