1966 (production)


 * In late April, the Doctor Who production office circulated a memo to writers outlining the proposed character of the Second Doctor, as well as suggestions on handling the first regeneration, which was initially compared to an LSD trip gone bad.
 * 6 August - The BBC announced to the press that William Hartnell was to leave the role of the first Doctor. Patrick Troughton signed a contract to play the second Doctor for 22 episodes.
 * 8 October - Episode 4 of The Tenth Planet was taped, with the first scenes filmed being the regeneration from William Hartnell to Patrick Troughton.
 * 22 October - Episode 1 of The Power of the Daleks was taped; this was the first full episode featuring Patrick Troughton.
 * 12 December - The BBC Audience Research Dept. filed an Audience Research Report on The Power of the Daleks Episode 3, reporting that satisfaction in the episode ranked at 44% with response to new Doctor Patrick Troughton being particularly mixed.
 * 15 December - Patrick Troughton was interviewed in Radio Times.