The then-Prince of Wales simply stopped picking up the phone to his son

Prince Harry’s phone calls were ignored by Charles after the Duke of Sussex swore at his father in a frustrated phone call, a new book claims.

In an explosive inside account of the deterioration of the relationship between the now King and his youngest son, highly-regarded royal author Robert Jobson explains how Charles became increasingly weary of the Sussexes’ demands for money.

He wrote in “Our King: Charles III” that Harry remained close to the late Queen after quitting the Royal Family and phoned her regularly from California.

However: “It troubled the Queen when he kept trying to air his grievances.”

Wishing not to get drawing into a row with the Duke of Sussex, the Queen instead asked him to phone his father.

A source told Jobson: “Her Majesty found Prince Harry’s calls quite difficult and wearisome.

“She didn’t want to interfere in the father/son relationship and would urge him to speak to his father.”

The phone calls between Charles and Harry are said to have been tense, with the Prince of Wales repeatedly facing demands for more money.

King Charles did not want to appear like a bank

“Prince Charles simply stopped taking Harry’s calls after his son swore at him and repeatedly asked for funds,” according to Jobson.

“When the Queen asked Charles why he hadn’t given in, he told her that he wasn’t a bank.”

Despite the clashes, the now King continues to have “enduring love for his son”, with the book even claiming the monarch fights the Duke and Duchess’s corner in conversations with aides.

Jobson’s book claims the continued use of the titles “the Duke and Duchess of Sussex” has been “discussed at the highest level”.

The author wrote: “The King is said not to be in favour, but other senior Royals are less indulgent.

“Ultimately, despite Charles’s enduring love for his son, he will come under increasing pressure if Harry continues to attack the monarchy.

“At that point, the King would have two options: put up with the spreading stain on his reign, or take action to limit its scope.

“In short, Harry and Meghan could yet find themselves demoted to Mr and Mrs Mountbatten-Windsor of Montecito, California.”