After the announcement of his cancer, King Charles III “remains and will remain king”. If his condition were to worsen, a form of “soft” regency could be put in place, explains Robert Hazell, professor in the department of the Constitution at University College of London.
A regency can only be declared if the monarch is, by law, incapable of carrying out his royal duties due to infirmity of body or mind. This is the constitutional limit if the king becomes unfit to fulfill his duties.