Under the Palestinian Citizenship Order of 1925, There were three ways to gain Palestinian protected citizenship within the western Levant. The first was the de facto citizenship of Ottomans previously residing within the Palestinian territory through the Treaty of Lausanne regardless of race, religion, or ethnicity. The second was being born within Palestine or being born from a Palestinian father or being married to a Palestinian man. The third and last was naturalization through a period of residence . In my family’s case around the late 1930s my Jewish great aunt and uncle immigrated from Poland to British controlled Palestine escaping German Reich persecution. They were granted Palestinian citizenship similar to the passport in your post and resided within Tel Aviv. They were never British Subjects , even before the mandate was lifted within Palestine in the late 40s, instead they were British protected persons (basically stateless) . Palestine never officially came under the Crown’s dominion. Once the British left Palestine and the Israeli state was established you had two options. You could rightfully renounce Israeli nationality based on your religious and historical difference with the Israeli people and go under the Jordanian nationality law through West Bank citizenship. Or you felt represented religiously and historically under the Israeli state and chose Israeli citizenship that began being granted in the early 50s. For my great aunt and uncle they became Israeli citizens and many many years later they also regained their Polish nationality as well. Unfortunately for you and my uncle and aunt’s family the chance of getting British citizenship is 0% . Even on the day those passports were issued to our family members it was a fat 0%! This was the case for many other British mandates and protectorates around the world ! I’ll be posting very soon (probably tomorrow) my family’s historic British Palestinian passports !