Her Majesty may, for the purpose of implementing any international agreement or otherwise, by Order in Council provide that any part of the territorial sea adjacent to the United Kingdom shall extend to such line other than that provided for by subsection (1) above as may be specified in the Order.

In any legal proceedings a certificate issued by or under the authority of the Secretary of State stating the location of any baseline established under subsection (1) above shall be conclusive of what is stated in the certificate.

As from the coming into force of this section the Territorial Waters Order in Council 1964 and the Territorial Waters (Amendment) Order in Council 1979 shall have effect for all purposes as if they were Orders in Council made by virtue of subsection (1)(b) above; and subsection (5) below shall apply to those Orders as it applies to any other instrument.

Subject to the provisions of this Act, any enactment or instrument which (whether passed or made before or after the coming into force of this section) contains a reference (however worded) to the territorial sea adjacent to, or to any part of, the United Kingdom shall be construed in accordance with this section and with any provision made, or having effect as if made, under this section.

Without prejudice to the operation of subsection (5) above in relation to a reference to the baselines from which the breadth of the territorial sea adjacent to the United Kingdom is measured, nothing in that subsection shall require any reference in any enactment or instrument to a specified distance to be construed as a reference to a distance equal to the breadth of that territorial sea.

In this section “nautical miles” means international nautical miles of 1,852 metres.