Section 39 Duties in UK merely incidental to duties outside UK

(1) This section applies if in a tax year an employment is in substance one whose duties fall to be performed outside the United Kingdom.

(2) Duties of the employment performed in the United Kingdom whose performance is merely incidental to the performance of duties outside the United Kingdom are to be treated for the purposes of this Chapter as performed outside the United Kingdom.

(3) This section does not affect any question as to—

(a) where any duties are performed, or

(b) whether a person is absent from the United Kingdom,

for the purposes of section 378 (deduction from seafarers' earnings: eligibility), and section 383 (place of performance of incidental duties) applies instead.