The Doctor (Doctor Who) and therefore cannot be spoken. The character played by Peter Cushing in the films "Dr. Who and the Daleks" and "" referred to himself as "Dr. Who". However, these films are not considered part of the same narrative continuity as the television programme, as they were based upon two television serials featuring William Hartnell and made considerable alterations to the characters of the Doctor and his companions. Quite apart from his name, why the Doctor uses the title "The Doctor" has never been fully explained on screen. The Doctor, at first, said that he was not a physician, often referring
The Invasion (Doctor Who) Chen in "The Daleks' Master Plan" (1965–66) and would later play Tyrum in "Revenge of the Cybermen" (1975). Peter Halliday, who plays Packer, also supplied the voice of the Cyber-Director in all eight episodes of the serial, in addition to the Cybermen voices in the last four episodes. In addition, Halliday went on to do several other roles (both voice and acting) in several later serials in the series. Edward Burnham also portrays Professor Kettlewell in the Tom Baker serial, "Robot" (1974–75). Clifford Earl previously played the station sergeant in "The Daleks' Master Plan". Sheila Dunn previously played Blossom Lefavre