Holby City is a British medical drama television series that premiered on 12 January 1999 on BBC One. The series was created by Tony McHale and Mal Young as a spin-off from the established BBC medical drama Casualty. It is set in the same hospital as Casualty, Holby General, in the fictional city of Holby, however Holby City is filmed at Elstree Studios in Borehamwood, while Casualty is filmed in Cardiff. Occasional crossovers between the two shows are broadcast as Casualty@Holby City. In 2006, HolbyBlue, a police procedural spin-off from Holby City, went into production. Its second season launched with a Holby City crossover episode.
Holby City follows the lives of surgeons, doctors, nurses, other medical and ancillary staff and patients on the hospital wards. Sixteen series of the show have aired, and a seventeenth began airing on 14 October 2014. The show's first series ran for nine episodes. The second and third series ran for sixteen and thirty episodes respectively, with new episodes then airing on a weekly basis from the fourth series onwards. Series four to nine and eleven all ran for 52 episodes, while series ten ran for 53 episodes. The show typically airs on Tuesdays in the 8:00 pm timeslot, although it is occasionally broadcast on a different day dependent on BBC scheduling. In 2007, the show temporarily moved to Thursday nights, allowing HolbyBlue to air in the 8:00 pm Tuesday timeslot. "Episode #" refers to the episode's number in the overall series, whereas "Series #" refers to the episode's number in each particular series.
Of the nine crossover episodes broadcast as Casualty@Holby City, five aired in the regular Casualty timeslot, while the remaining four—"Casualty@Holby City: Part Two", "Test Your Metal", "A Great Leap Forward" and "Deny Thy Father: Part Two"—were broadcast in the Holby City timeslot.