SolvedDT14805 | Double Taxation Relief Manual: Oman: pensions and annuities
From HM Revenue & Customs · Double Taxation Relief Manual
Occupational pensions and employer provided annuities paid to a United Kingdom resident from a source in Oman are exempt from Omani tax under Article 18.
Similarly, social security pensions paid from Oman to a United Kingdom resident are taxable only in the United Kingdom (Article 22(1)).