For every port/harbour, an individual Act of Parliament (or, more recently, a Harbour (Revision) Order) can incorporate parts of the Harbours, Docks, and Piers Clauses Act 1847 (HDPCA) and apply them to that specific port/harbour. Officers of port police forces are sworn in as "special constables" under section 79 of the 1847 Act, as incorporated by the individual local Act. As a result, officers have the full powers of a constable on any land owned by the harbour, dock, or port and at any place within one mile of any owned land.