EIM40208 | Employee resident or domiciled outside the United Kingdom: location of duties: workers in the offshore oil and gas industry
From HM Revenue & Customs · Employment Income Manual
Section 41 ITEPA 2003
Special rules cover general earnings for duties performed in the UK sector of the continental shelf. General earnings arising from duties performed in a designated area in connection with exploration or exploitation activities are treated as general earnings in respect of duties performed in the UK (see EIM67100 onwards for full information).