Claim: Doctor Who is a television show.

Torchwood -LRB- -LSB- ` tawrch , wUd -RSB- -RRB- is a British science fiction television programme created by Russell T Davies . A spin-off from the 2005 revival of long-running science fiction programme Doctor Who , Torchwood aired four series between 2006 and 2011 . The show shifted its broadcast channel each series to reflect its growing audience , moving from BBC Three to BBC Two to BBC One , and acquiring US financing in its fourth series when it became a co-production of BBC One and Starz . In contrast to Doctor Who , whose target audience includes both adults and children , Torchwood is aimed at an older audience . Over its run , the show explored a number of themes ; prominent among these were existentialism , homosexual and bisexual relationships , and explorations of human corruptibility .   Torchwood follows the exploits of a small team of alien hunters , who make up the Cardiff-based , fictional Torchwood Institute , which deals mainly with incidents involving extraterrestrials . Its central character is Captain Jack Harkness -LRB- John Barrowman -RRB- , an immortal former con-man from the distant future ; Jack originally appeared in the 2005 series of Doctor Who . Other than Barrowman , the initial main cast of the series consisted of Eve Myles , Burn Gorman , Naoko Mori , and Gareth David-Lloyd . Their characters are specialists for the Torchwood team , often tracking down aliens and defending the planet from alien and nefarious human threats . In its first two series , the show uses a time rift in Cardiff as its primary plot generator , accounting for the unusual preponderance of alien beings in Cardiff . In the third and fourth series , Torchwood operate as fugitives . Gorman and Mori 's characters were written out of the story at the end of the second series . Recurring actor Kai Owen was promoted to the main cast in series three , in which David-Lloyd too was written out . Subsequently , American actors Mekhi Phifer , Alexa Havins , and Bill Pullman joined the cast of the show for its fourth series .   The first series premiered on BBC Three and on BBC HD in 2006 to mixed reviews , but viewing figures which broke records for the digital channel . It returned in 2008 where it aired first on BBC Two , receiving a higher budget ; its uneven tone , a criticism of the first series , was largely smoothed out , and the show attracted higher ratings and better reviews . The third series episodes worked on a higher budget and transferred to the network 's flagship channel , BBC One , as a five-episode serial , entitled Torchwood : Children of Earth . Although Children of Earth was broadcast over a period of five consecutive summer weeknights , the show received high ratings in the United Kingdom and overseas . A fourth series , co-produced by BBC Wales , BBC Worldwide , and US premium entertainment network Starz aired in 2011 under the title Torchwood : Miracle Day . Set both in Wales and the United States , Miracle Day fared less well with critics than the previous series , though was applauded by some for its ambition . In October 2012 , Davies announced that for personal reasons the show would enter indefinite hiatus .   All four series have been broadcast in Asia , Australia , New Zealand , Europe , and North America . Owing to the early popularity of Torchwood , various tie-in media were produced , including audio dramas , novels and comic strips . From its inception , the BBC invested in a heavy online presence for the series , with an alternate reality game running alongside the show 's first two series , and an animated Web series running alongside its fourth . The BBC continued to approve and commission licensed spin-offs after the show 's conclusion , including a 2015 audio series from Big Finish Productions .