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Official Site: BBC

The Fourth Doctor is the fourth incarnation of the protagonist of the long-running BBC British television science-fiction series Doctor Who.

He was portrayed by Tom Baker for seven consecutive seasons (from December 28, 1974 (Part One of Robot) to March 21, 1981 (Part 4 of Logopolis), and remains the longest-lived incarnation of the Doctor in the show's on-screen history, counting both the classic and modern series.

Within the series' narrative, the Doctor is a centuries-old Time Lord alien from the planet Gallifrey who travels in time and space in his TARDIS, frequently with companions. When the Doctor is critically injured, he can regenerate his body, changing his physical appearance and personality in the process.

The Fourth Doctor appeared in 172 episodes (179, counting the regeneration in Planet of the Spiders and the aborted Shada) over a seven-year period, from 1974 to 1981. This makes him the longest running on-screen Doctor of both series. He also appeared in the specials The Five Doctors (via footage from the incomplete Shada) and made his final appearance as the Doctor in the charity special Dimensions in Time (aside from a series of television advertisements in New Zealand in 1997 ).

The Fourth Doctor has not been a contender in any CBUB matches.