When the first season was being made, television pirates were desperate to acquire the preview tapes. One of the people in the office had the idea of labelling 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 for the Torchwood institution and then when creating the spin-off series Torchwood (2006).
Julie Gardner has said that when David Tennant was approached to play the Tenth Doctor, he was immediately enthusiastic. His first response was to ask, "Can I have a long swishy coat?"
Peter Capaldi had appeared on the show in a different role before being cast as the Twelfth Doctor, but Colin Baker did too in the original, so this is not the first time an actor playing the Doctor had previously appeared as a different character on the show. Coincidentally, Capaldi appeared in the episode in which Karen Gillan had a different role before being cast as a full-fledged companion, The Fires of Pompeii (2008).
Writer and executive producer Russell T. Davies had Christopher Eccleston's name on a shortlist for the role of The Doctor, but didn't really think that he would accept the role because of his reputation as a very serious actor with a background in hard-hitting dramas. However, Eccleston was such a big fan of Davies as a writer that he got in contact to ask if he could audition for the part. Eccleston had not been a fan of the original series, so he watched The Talons of Weng-Chiang: Part One (1977), one of the most popular serials from the original run and a particular favorite of Davies' for the quality of its dialogue, as part of his preparation.