The Constitution Unit at University College London (UCL) explain: “Charles was created Prince of Wales in 1958 when he was aged 10, with an investiture at Caernarvon Castle in 1969.
“As an adult, Prince William might expect to become Prince of Wales soon after his father’s accession; but that will be a matter for the new King to decide because, strictly, the title is not heritable.”
Had Princess Charlotte been born before Prince George, however, she would not have been eligible for the title under the current rules.
The Prince of Wales title is given to the male heir apparent, and therefore Charlotte would not have been appointed Princess of Wales.
