Holby is a fictional city in the United Kingdom, in which BBC medical dramas Casualty, and Holby City, and police drama HolbyBlue are set. It was based upon the city of Bristol, where Casualty was formerly filmed, and is located in the fictional county of Wyvern in the South-West of England, not far from the Welsh border. While Casualty has been filmed in Cardiff since 2011, Holby City is filmed in Elstree, Hertfordshire. Both shows are set in the same fictional Holby City Hospital.