British Nationality could be obtained through your birth, or through the birth of any one of your parents or grandparents, in Oman. This arises because of Britain's relationship with Muscat and Oman and Britain's Colonial history.
To determine what form of British Nationality you might have, an analysis of your family's history must be done, and then applying it to the Nationality laws of Oman that have been passed over the years.
STATUS OF OMAN (previously Muscat & Oman)
From 22.07.1840 up until 31.12.1966, the Crown acquired extra-territorial jurisdiction over Muscat and Oman. Gwadur (on the south coast of what is now Pakistan) was included in this but only up until 07.09.1958.
From 01.01.1967, Oman became a foreign country.
On 30.11.1967, the Kuria Maria Islands (formerly part of the Aden Colony) acceded to Oman.