In keeping with the Letters Patent issued when George VI gave Philip the title in 1947, the Prince of Wales, as the Duke’s eldest son, inherits the title the Duke of Edinburgh.
But on Charles’s eventual accession to the throne the title can be regranted anew to Edward.
A title held by someone who becomes monarch is said to merge with the Crown and ceases to exist, so can be recreated.
The Palace stated in 1999 that the Queen, Philip and Charles had agreed that Edward would become the Duke of Edinburgh in due course.
Edward’s wife, the Countess of Wessex, will become the Duchess of Edinburgh– a courtesy title which was held by the Queen.
Sophie Rhys-Jones and Prince Edward were given the titles the Earl and Countess of Wessex in 1990
Philip was the sixth person – including two Dukes of Gloucester and Edinburgh – to bear the title the Duke of Edinburgh.
The first was George I’s grandson Prince Frederick, later the Prince of Wales, for whom the title was first created in the Peerage of Great Britain in 1726.
George VI gave Philip the titles of the Duke of Edinburgh, Earl of Merioneth and Baron Greenwich in the Peerage of the United Kingdom shortly before his marriage to Princess Elizabeth in 1947.
Philip’s great-great-uncle, Prince Alfred Ernest Albert, fourth child and second son of Queen Victoria and Prince Albert, was also a Duke of Edinburgh in the Peerage of the United Kingdom.
Source: EXPRESS CO UK