For a seafarer to qualify for the deduction, a qualifying period of at least 365 consecutive days needs to be set up, which can include non-work days. This period can straddle more than one tax year.
Duties are regarded as being performed outside the UK if they are carried out on a vessel where the voyage or part voyage begins or ends outside the UK. The UK sector of the North Sea is treated as part of the UK. There must also be at least one foreign port visit in each employment in each tax year.
Visits to the UK must not exceed 183 consecutive days nor one half of the qualifying period by counting midnights. For the latter, the period concerned runs from the first day abroad to the last day of the period spent abroad, after the previous visit spent in the UK: