Casualty is a British medical drama television series that premiered on 6 September 1986 on BBC1. The series was created by Jeremy Brock and Paul Unwin. It is set in the fictional Holby City Hospital, in the equally fictitious city of Holby, and features occasional crossovers of characters and plots with spin-off show Holby City. Casualty follows the professional and personal lives of the doctors, nurses, paramedics, hospital management and patients at Holby General. It features an ensemble cast of regular characters, and began with ten main characters in its first series, including the longest-serving character Charlie Fairhead (played by Derek Thompson). They have all since left the series. Many main characters have been written in and out of the series since. In addition, Casualty features guest stars each week, as well as recurring guests that take part in story arcs that span a portion of a series or multiple series.