sentences:  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 were broadcast as "Casualty@Holby City".In 2006, "HolbyBlue", a police procedural spin-off from "Holby City", went into production.