Is it permissible for a Christian woman who is chaste to marry a Muslim man without the permission or consent of her Christian guardian?

It is not permissible for a chaste Kitābiyyah (woman of the People of the Book) to marry a Muslim without the permission of her Kitābī guardian, due to the Prophet’s (peace be upon him) saying: "There is no marriage except with a guardian." Her disbelieving guardian may marry her to a Muslim, because he is her guardian, so his performing the marriage is valid.