The only surviving footage of the first regeneration of Doctor Who (1963) (from William Hartnell to Patrick Troughton in 1966) exists due to a clip used in Blue Peter.
It is currently the longest running children's television show in the world.
Of the period 16th October 1958 to 5th November 1962, only two clips from the show are known to be archived. Approximately 312 editions survive from between 12 November 1962 and 9th December 1968, whilst (thanks to long-term series editor Biddy Baxter) every episode exists from Thursday 12th December 1968 onwards.
The series was used by the BBC as a platform to launch several upcoming programs aimed at children, in particular Doctor Who (1963). Long-running presenter Peter Purves had played a companion to William Hartnell's Doctor before joining Blue Peter and Janet Ellis had also acted in a Doctor Who (1963) serial starring Tom Baker before joining as a presenter.
The title music is called "Barnacle Bill", composed by Herbert Ashworth-Hope. The original, "classic", version used from October 1958 to January 1979, was played by Sidney Torch and The New Century Orchestra.