Third Doctor

The Third Doctor is an incarnation of the Doctor, the protagonist of the British science fiction television series Doctor Who. He was portrayed by actor Jon Pertwee. Within the series' narrative, the Doctor is a centuries-old alien Time 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. Consequently, both the physical appearance and personality of the Doctor changes. Preceded in regeneration by the Second Doctor (Patrick Troughton), he is followed by the Fourth Doctor (Tom Baker). Pertwee portrays the Third Doctor as a dapper man of action, in stark contrast to his wily but less action-orientated predecessors. While previous Doctors' stories had all involved time and space travel, for production reasons Pertwee's stories initially depicted the Doctor stranded on Earth in exile, where he worked as a scientific advisor to the international military group UNIT. Within the story, the Third Doctor came into existence as part of a punishment from his own race, the Time Lords, who forced him to regenerate and also disabled his TARDIS. Eventually, this restriction is lifted and the Third Doctor embarks on more traditional time travel and space exploration stories. His initial companion is UNIT scientist Liz Shaw (Caroline John), who leaves the Doctor's company between episodes to be replaced by Jo Grant (Katy Manning), who then continues to accompany the Doctor after he regains use of his TARDIS. His final companion is journalist Sarah Jane Smith (Elisabeth Sladen).