The condition at Section 378(1)(b) specifies:
“the duties of the employment (as a seafarer) are performed wholly or partly outside the United Kingdom ...”
However the legislation is silent as to the amount of duties
that will satisfy the condition. There is no de minimis limit
prescribed.
There are special rules for deciding whether the duties of a
seafarer's employment have been performed wholly or partly outside
the United Kingdom for the purposes of the deduction.
Section 383(4)(a) ensures that incidental duties performed in
the United Kingdom are not treated as performed outside the United
Kingdom for the purposes of the seafarers' deduction. Whether
duties have been performed in the United Kingdom is therefore a
question of fact.
Section 383(1) treats duties performed by a seafarer outside
the United Kingdom as performed in the United Kingdom where:
If substantive duties of the employment are carried out abroad in a tax year, then the condition in Section 378(1)(b) will be satisfied. The idea underlying substantive or merely incidental duties is based on the quality not the quantity of duties (see EIM40203).
An engineer who normally works on ships engaged on voyages between United Kingdom ports is required to carry out the same duties on a ship engaged on a voyage between Rotterdam and Norway. The voyage lasts for one week so in that year the duties of her employment as a seafarer are performed partly outside the United Kingdom. However, the deduction will not be due unless she also has an eligible period of at least 365 days. In the circumstances of the example this is unlikely.
