Torchwood is an anagram of Doctor Who. When the first series of the new Doctor Who (2005) was being made, television pirates were desperate to acquire the preview tapes. One of the people in the office had the idea of labeling the tapes with the anagram 'Torchwood' rather than Doctor Who, as a security measure to disguise the tapes when they were delivered from Cardiff to London. Writer Russell T Davies liked this idea so much that it later inspired him to use it as a title when creating this spin-off series.

Torchwood was formed in 1879 by the Royal decree of Queen Victoria as a result of her experiences in Doctor Who: Series 2: Tooth & Claw.

Torchwood is separate from the Government, outside the Police, beyond the United Nations. More secret than MI5 or MI6, not even the Government is supposed to know about them.

The Torchwood Hub is situated deep beneath Cardiff Millennium Centre.

John Barrowman first appeared as Captain Jack Harness in Episode 9 (The Empty Child) of the 2005 series of Doctor Who. He also appeared in The Doctor Dances, Boom Town, Bad Wolf and The Parting of the Ways in the 2005 series, and again in the episodes Army of Ghosts and Doomsday in the 2006 series.

John used to present the UK children's show Live and Kicking in 1993. He has also starred in a number of West End stage musicals.

The part of Gwen in Torchwood was written specially for Eve Myles. She first appeared as Gwyneth in Episode 3 (The Unquiet Dead) of the 2005 series of Doctor Who.

Burn Gorman (Owen Harper) received critical acclaim for his hugely popular role of Guppy in the BBC's award-winning 2005 adaptation of Dickens' Bleak House.

Naoko Mori (Toshiko Sato) is best known for her role as Saffy's best friend Sarah (aka Titicaca), in the comedy series Absolutely Fabulous. She first appeared as Dr Sato in Episode 4 (Aliens of London) of the 2005 series of Doctor Who.