140All trade by sea from one part of the United Kingdom to another to be deemed coastwise, and no part to be deemed beyond the sea.
All trade by sea from any one part of the United Kingdom to any other part thereof shall be deemed to be a coasting trade and all ships while employed therein shall be deemed to be coasting ships, and no part of the United Kingdom, however situated with regard to any other part, shall be deemed in law, with reference to each other, to be parts beyond the seas; and if any doubt shall at any time arise as to what or to or from what parts of the coast of the United Kingdom shall be deemed a passage by sea, the Commissioners of the Treasury may determine and direct in what cases the trade by water from one port or place in the United Kingdom to another of the same shall or shall not be deemed a trade by sea within the meaning of this or any Act relating to the Customs.