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 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 Who. 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 broken down into four shorter serials with an overarching theme. This format was again reused in the third and fourth series of Torchwood. The trial storyline itself acted as a framing device to bracket the story. In the last two episodes, commonly known as The Ultimate Foe, the trial took centre stage.

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; following its conclusion, Baker was fired. He did not return to play the Doctor for the regeneration that led off the next 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.

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 arc), and The Ultimate Evil. An unofficial audio adaptation of The Nightmare Fair was also produced for charity in the early 2000s.

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)

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