25Meaning of “treaty” and “ratification”E+W+S+N.I.
(1)In this Part “treaty” means a written agreement—
(a)between States or between States and international organisations, and
(b)binding under international law.
(2)But “treaty” does not include a regulation, rule, measure, decision or similar instrument made under a treaty (other than one that amends or replaces the treaty (in whole or in part)).
(3)In this Part a reference to ratification of a treaty is a reference to an act of a kind specified in subsection (4) which establishes as a matter of international law the United Kingdom's consent to be bound by the treaty.
(4)The acts are—
(a)deposit or delivery of an instrument of ratification, accession, approval or acceptance;
(b)deposit or delivery of a notification of completion of domestic procedures.