The show is a significant part of British popular culture, and elsewhere it has become a cult television favourite. The show has influenced generations of British television professionals, many of whom grew up watching the series. The programme originally ran from 1963 to 1989. There was an unsuccessful attempt to revive regular production in 1996 with a backdoor pilot, in the form of a television film. The programme was relaunched in 2005 by Russell T Davies, who was showrunner and head writer for the first five years of its revival, produced in-house by BBC Wales in Cardiff. The first series of the 21st century featured Christopher Eccleston in the title role and was produced by the BBC. Doctor Who also spawned spin-offs in multiple media, including Torchwood (2006–2011) and The Sarah Jane Adventures (2007–2011), both created by Russell T Davies; K-9 (2009–2010); and a single pilot episode of K-9 and Company (1981). There also have been many spoofs and cultural references to the character in other media.
Which of the spin-offs mentioned started and ended in the 20th century?