The Territorial Waters Jurisdiction Act, 1878 was enacted to determine the jurisdiction of the territorial waters and to regulate the law relating to the trial of offences committed on the Sea within a certain distance of the Coasts of Her Majesty’s Dominions. The preamble of the Act states that the rightful jurisdiction of Her Majesty, her heirs and successors, extends and has always extended over the open seas adjacent to the coasts of the United Kingdom and of all other parts of Her Majesty’s dominions to such a distance as is necessary for the defence and security of such dominions. ‘Territorial waters’ has been defined under the Act as : “The territorial waters of Her Majesty's dominions in reference to the sea means such part of the sea adjacent to the coast of the United Kingdom, or the coast of some other part of Her Majesty's dominions, as is deemed by international law to be within the territorial sovereignty of Her Majesty; and for the purpose of any offence declared by this act to be within the jurisdiction of the admiral, any part of the open sea within one marine league of the coast measured from low-water mark shall be deemed to be open sea within the territorial waters of Her Majesty's dominions.” The jurisdiction under this Act is exercised without any distinction between territorial waters and inland waters. It is provided that an offence committed by a person, whether he is or is not a subject of Her Majesty, on the open sea within the territorial waters of Her Majesty's dominions, is an offence within the jurisdiction of the Admiral, although it may have been committed on board or by means of a foreign ship, and the person who committed such offence may be arrested, tried and punished accordingly.
