If a British woman marries her Iranian fiance in Iran according to Iranian laws does she lose her British nationality and can she have both an Iranian and British Passport?

Answer 1

Yes, you can have the two passports. According to Iranian law any foreign woman who marries an Iranian man is automatically a citizen of Iran and,unless the other country of nationality prevents them from doing so, theycan retain their foreign nationality. In this case, the UK does allow you to keep your British nationality.
Trivia to know (but not get scared):

• You should enter and depart Iran using your Iranian passport (but also have your British one with you ALWAYS);
• Iran does not prevent its citizens from obtaining other nationalities. However, it continues to recognize its citizens solely as Iranians (this includes foreign women who marry an Iranian man);
• A boy who has an Iranian father and a foreign mother, is still considered an Iranian citizen only- despite dual nationality- and must perform military service in the year which they turn 18. On that year, the child is prevented from exiting Iran unless the parents have purchased his military service if the child meets the eligibility requirements.