a number of other countries do not allow multiple citizenship. if a person has british nationality and is also a national of a country that does not allow dual nationality, the authorities of that country may regard the person as having lost that nationality or may refuse to recognise the british nationality. british nationals who acquire the nationality of a country that does not allow dual nationality may be required by the other country to renounce british nationality to retain the other citizenship. none of this affects a person's national status under uk law.