The longest running SF television series has been been successfully produced by BBC since 1963. It is the only SF television programme to hold the world record for the highest number of episodes - BBC has already aired 35 seasons of the series (815 episodes!). Today it makes a significant part of British pop-culture.

Many charismatic actors have played the famous Doctor, including all four of the names in the question. William Hartnell was the first (1963-66), however, Tom Baker (1974–81) was one of the best known. Christopher Eccleston appeared briefly (2005), and John Hurt appeared in the Doctor Who 50th anniversary episode as a 'forgotten' incarnation.

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