The Waterguard was the name given to a division of HM Customs and Excise responsible for the control of vessels, aircraft, vehicles and persons arriving into and departing from the United Kingdom. This included crew members and passengers, as well as persons travelling on foot. Waterguard officers were responsible for applying the allowances provided for in law and for collection of customs and excise revenue on the excess. The officers were also responsible for the enforcement of the prohibitions and restrictions, including controlled drugs and plant and animal health. It officially ceased to exist in 1972, with the reorganization of HM Customs and excise.
Formed in 1809 as the "Preventive Waterguard" (also known as the Preventative Boat Service) to combat smuggling, the Waterguard was the sea-based arm of revenue enforcement and complemented the "riding officers" who patrolled the shore. The Waterguard was initially based in Watch Houses around the coast, and boat crews patrolled the coast in cutters each night. It was under Admiralty control from 1816 to 1822, when it and riding officers were amalgamated under the control of the Board of Customs. The Waterguard was absorbed into the Customs and Excise department in 1909.
Members of the Waterguard were uniformed officers whose uniform was very similar to that of a Royal Navy officer. The most noticeable difference was that the bands of rank extended only halfway around the sleeve, instead of forming a continuous band. The name "Waterguard" became misleading after 1923, when their domain was extended to the border between Northern Ireland and the Irish Free State (now the Republic of Ireland), and they also came to carry out controls at airports and other places of entry into the United Kingdom. Waterguard officers were often referred to simply as "customs officers", although until 1972 Officers of Customs and Excise were non-uniformed and were responsible for the examination and clearance of cargo (rather than passengers), as well as control of Purchase Tax. When Purchase Tax was replaces by VAT, control of this tax became the responsibility of HM Customs and Excise. Prior to 1972, the basic grade in the Waterguard was that of Assistant Preventive Officer, and advancement could made through the ranks to the grades of Preventive Officer then Chief Preventive Officer, initially by way of written examination then interview. Further advancement was possible within the Waterguard structure, up to the highest grade of Inspector General of Waterguard. Even though it officially ceased to exist from 1972, with the reorganization of HM Customs and Excise, the functions of the Waterguard continued to be carried out for many years afterwards.
- House of Commons Sessional Papers 1819 (569) XVII, 77; "A Return of Officers and Men appointed to the Preventative Boat Service between November 1816 and March 1819"