Income and Corporation Taxes Act 1988

5 Notwithstanding section 132(4)(b), there shall be treated for the purposes of section 193(1) and this Schedule as performed outside the United Kingdom any duties which a person performs on a vessel or aircraft engaged on—

(a) a voyage or journey beginning or ending outside the United Kingdom (but exclusive of any part of it which begins and ends in the United Kingdom); or

(b) any part beginning or ending outside the United Kingdom of a voyage or journey which begins and ends in the United Kingdom;

and for the purposes of this paragraph any area designated under section 1(7) of the [1964 c. 29.] Continental Shelf Act 1964 shall be treated as part of the United Kingdom.