Sixth Doctor

The Sixth Doctor is an incarnation of the Doctor, the protagonist of the British science fiction television series Doctor Who. He is portrayed by Colin Baker. Within the series' narrative, the Doctor is a centuries-old alienTime Lord from the planet Gallifrey who travels in time and space in the TARDIS, frequently with companions. At the end of life, the Doctor regenerates; as a result, the physical appearance and personality of the Doctor changes. Baker portrays the sixth such incarnation: conceived by producer John Nathan-Turner and Baker to be an arrogant and abrasive character. The Sixth is flamboyantly dressed in brightly coloured, mismatched clothes with a patronising personality intentionally written and portrayed to set him apart from all his previous incarnations.

Preceded in regeneration by the Fifth Doctor (Peter Davison), he is followed by the Seventh Doctor (Sylvester McCoy). The Sixth Doctor appeared in two seasons, although his first regular appearance was in The Twin Dilemma (1984), the final story of season 21. The Sixth appeared with only two companions on-screen, most notably the American college student Peri Brown (Nicola Bryant), who had travelled with his previous incarnation, before being briefly joined by Mel Bush (Bonnie Langford), a computer technician from his future.

Prior to its hiatus, season 23 was well into preproduction, with episodes under active development before BBC1 executive Michael Grade forcibly paused all production on Doctor Who. Once it was allowed to return, the planned production for season 23 was dropped in favour of the 14-episode story arc The Trial of a Time Lord. Unsatisfied with Baker's performance, Grade demanded Nathan-Turner terminate him from the role if Doctor Who was to be renewed for further seasons, despite Baker having signed up for four years. Baker, displeased by the treatment he received from the production during his tenure, refused to return to film his regeneration at the beginning of Time and the Rani (1987), offering instead to return for one last season where he would regenerate at the end, but receiving no further response after his counter-offer.

The Sixth Doctor's time on television received frequent criticism for its violence, darker tone compared to prior seasons of the show, and antagonistic relationship between the Doctor and companion Peri. Since the end of the Sixth Doctor's run, novels and audio plays have featured the character in further adventures, most prominently in those commissioned by Big Finish Productions; they have also been visually referenced several times in the revived 2000s production of the show. Baker eventually returned to play the role in the show 36 years after he had been fired to film a cameo as the Sixth Doctor in "The Power of the Doctor" (2022), where he appeared among multiple other past incarnations as figments within the consciousness of the Thirteenth Doctor (Jodie Whittaker).