Prince Edward taking on his late father's ducal title would interfere with the King's plans to reduce the number of family members working on his behalf and depending on the royal purse. Prince Edward was expected to inherit his father's title of Duke of Edinburgh once it merged into the Crown following King Charles's accession.
But speculation has now been rocketing about the sovereign opting out of the agreement he struck with the late Queen and Prince Philip, and not bestowing the title on his younger brother. Royal commentator Richard Eden suggested the change of plans falls in line with the King's vision for the future of the Royal Family, as the ducal title would continue to pass on to Edward's descendants until the line runs out.
Speaking to Palace Confidential, Mr Eden said: "Charles has decided he's not going to give it to him, he's not going to really use it himself.
"That title stays with the Crown but he doesn't want to give it to him. One of the reasons is that it's a hereditary title, if he gives it to Edward, it then establishes a new household.
"You've got the Duke and Duchess of Edinburgh, their son James would inherit that title.
"The view that I was told from the King is that Edward always accepted that slimmed-down monarchy, that's why his children didn't become prince and princess." He added: "They had some title, Lady and Viscount, but not that prince title and he accepted that. And this is part of that slimming down."
Royal sources have since suggested the King is planning to hold on to the Edinburgh title to pass it on to his eldest granddaughter, Princess Charlotte, if she marries.
The insiders suggested the move would also serve as a tribute to the late Queen, who was styled the Duchess of Edinburgh from her wedding in 1947 until her accession in 1952.
They said: "Discussions are underway, but the favored outcome for the King is that this title ought to go to Princess Charlotte.
"It would be a fitting way to remember the Queen - who, of course, had the title Duchess of Edinburgh - and a way for His Majesty to honor the line of succession."