Regeneration (Doctor Who)

In the long running British science fiction television series Doctor Who, regeneration is a biological ability exhibited by the Time Lords, a race of fictional humanoids originating on the planet Gallifrey. This process allows a Time Lord who is old, wounded or otherwise dying to undergo a transformation into a new physical form and a somewhat different personality. The process has been used eleven times throughout the history of the franchise as a device for introducing a new actor for the lead role of its main character, the Doctor. The current incarnation of the Doctor is played by Peter Capaldi, following the regeneration of the Eleventh Doctor (portrayed by Matt Smith) during the 2013 Christmas special "The Time of the Doctor". Other Time Lords and similar characters have also regenerated, for various reasons, sometimes with change of actors.

The concept of regeneration was created in 1966 by the writers of Doctor Who as a method of replacing the leading actor. The role of the Doctor had been played by William Hartnell from the programme's inception in 1963 but, by 1966, it was increasingly apparent that Hartnell's health was deteriorating and he was becoming more difficult to work with. Producer John Wiles had, following several clashes with Hartnell, intended to have the actor replaced in The Celestial Toymaker; during two episodes of that serial, the Doctor is invisible (owing to Hartnell being on holiday during the recording). Wiles' plan was for the character to reappear played by a new actor. This proposal was vetoed by Gerald Savory, the BBC's Head of Serials (and Wiles' superior), which led to Wiles leaving before The Celestial Toymaker was produced. However, it was apparent that it would not be possible for Hartnell to continue for much longer.

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