By Royal Decree: King Charles Needs Archie and Lilibet Diana to Work for Shrinking Crown Since Ancient Rule Gives Him 'Full Custody' of Sussex Grandkids

King Charles has custody of Harry and Meghan's children based on centuries-old prerogative..MEGA/NETFLIX

King Charles III has "full custody" of Prince Archie and Princess Lilibet Diana thanks to an 18th-century prerogative. This custom could help the monarch due to his "shrinking" roster of senior royals.

"The fact they are still seventh and eighth in line to the thrown is quite extraordinary really and you never know one day they might be called into action," royal expert Phil Dampier shared when highlighting the Sussex kids' possible future with the Crown.

An image from Netflix's 2022 documentary, 'Harry & Meghan,' which shows brief glimpses of Prince Archie and Princess Lilibet Diana. NETFLIX

"They might move up the scale," he added. "It's all hanging a bit by a thread and I think when they get older they're going to start asking questions and say 'how did it come to this? That we haven't got a relationship with our grandparents or the royal family.'"

According to royal journalist Marlene Koenig, the 1717 prerogative, in which King George I introduced due to issues he was having with his heir, the future King George II, gave the sovereign jurisdiction over the custody of his/her grandchildren. This never extended to the late Queen Elizabeth II since Archie and Lilibet were her great-grandchildren, however, Koenig also highlighted how the prerogative resurfaced in the mid-1990s during the marital issues of the then-Prince Charles and Diana, Princess of Wales.

King Charles III has reportedly 'barely seen' his Sussex grandchildren. MEGA

Even though the royal decree exists, Koenig and other analysts feel that His Majesty "would never act" upon the prerogative.

"It would destroy his image and his reign would likely become deeply damaged as a result," a former palace insider stated. "That was all well and good for George I, whose era may as well be another planet entirely compared to today."

Prince Archie turned five on Monday, May 6, and the monarch is said to be "desperate" to have a relationship with his grandson and Princess Lilibet Diana.

The head of state is also said to be upset with his estranged son and daughter-in-law since they keep insisting he speak to his grandkids via video, which he dislikes. "Charles been asking about video calling, but according to his aides, he’s uncomfortable with the idea," royal author Tom Quinn pointed out. "If he makes an ordinary telephone call to Harry, it means he can have a quick word with Archie without the need to talk to Meghan, a prospect that fills him with dread."

King Charles III has 'theoretical rights and privileges that would shock many,' a royal insider shared. MEGA

Prince Archie memorably turned four on the same date as his grandfather's coronation, May 6, of last year. The Duchess of Sussex stayed in Montecito with both children while the Duke of Sussex attended the grand event at Westminster Abbey. It is believed that the Sussex kids have not been in the U.K. since June 2022, when Elizabeth II celebrated her Platinum Jubilee.

'Acting on such a cruel and archaic royal stance would destroy him,' a legal analyst said of the 300-year old prerogative Charles III possesses. MEGA

The Sun reported on Dampier's remarks.