Holby fictional hospital within the city in which "Casualty" and "Holby City" are set. It is based on the Bristol Royal Infirmary which the original script writers spent time observing in the 1980s in order to garner ideas for "Casualty". Although both shows are set in the same hospital, "Casualty" is primarily filmed in Cardiff, whilst "Holby City" is filmed in Hertfordshire at BBC Elstree Centre. The indoor shots for the first series of "Casualty" were filmed at BBC Television Centre in London. The exterior shots of the hospital used in "Casualty" were formerly filmed at the City of Bristol College;
Holby City is limited to "accident of the week" storylines about patients entering hospital, "Holby City" allowed the possibility of storylines about long-term care, rather than immediate life and death decisions. The series was commissioned by BBC One Controller Peter Salmon, and began airing on BBC One on 12 January 1999. Series producer Richard Stokes believes that the series' popularity stems from the fact the hospital setting presents numerous plotline opportunities, explaining: "You have licence to create life-and-death situations every week, something you cannot do in any other set piece. The interaction of the characters can be sexy and social issues also