The Doctor (Doctor Who)
The Doctor is the title character in the long-running BBC science fiction television programme "Doctor Who". Since the show's inception in 1963, the character has been portrayed by thirteen lead actors. In the programme, "the Doctor" is the alias assumed by a centuries-old alien—a Time Lord from the planet Gallifrey—who travels through space and time in the TARDIS, frequently with companions. The transition to each succeeding actor is explained within the show's narrative through the plot device of "regeneration", a biological function of the Time Lord race that allows a change of cellular structure and appearance with recovery following a potentially fatal injury.
Television show
British shows have tended toward shorter series in recent years. For example, the first series of long-running science fiction show "Doctor Who" in 1963 featured forty-two 25‑minute episodes, this dropped to twenty-five by 1970 to accommodate changes in production and continued to 1984. For 1985 fewer but longer episodes were shown, but even after a return to shorter episodes in 1986, lack of support within the BBC meant fewer episodes were commissioned leading to only fourteen 25‑minute episodes up to those in 1989 after which it was cancelled. The revival of "Doctor Who" from 2005 has comprised thirteen 45‑minute installments. However, there are some series in the UK that have a larger number of episodes, for example "Waterloo Road" started with 8 to 12 episodes, but from series three onward it increased to twenty episodes, and series seven will contain 30 episodes. Recently, American non-cable networks have also begun to experiment with shorter series for some programs, particularly reality shows, such as "Survivor". However, they often air two series per year, resulting in roughly the same number of episodes per year as a drama.