(1)A person does not commit an offence under Part 3, 4, 10 or 11 of this Act if—
(a)the conduct which would otherwise constitute the offence takes place on board a vessel (within the meaning of section 353(1)), and
(b)the vessel is on a journey which has taken it or is intended to take it into international waters.
(2)Subject to subsection (1) a provision of this Act which applies in relation to a thing done in Great Britain applies to that thing if done on or in the territorial sea adjacent to Great Britain.
(3)In this section—
“international waters” means waters outside the territorial sea adjacent to Great Britain, and
“the territorial sea” has the meaning given by section 1 of the Territorial Sea Act 1987 (c. 49).