Prince Philip, Prince Charles and Queen Elizabeth II
Queen Elizabeth II and Prince Philip doubt Prince Charles' suitability as the next monarch. Pictured: Queen Elizabeth II, Prince Philip and Prince Charles attend the wedding ceremony of Britain's Princess Eugenie of York and Jack Brooksbank at St George's Chapel, Windsor Castle, in Windsor, on Oct. 12, 2018. Getty Images/Owen Humphreys

Queen Elizabeth II and Prince Philip are not confident with Prince Charles' suitability as the next king.

According to Robert Jobson, a journalist for Daily Mail, the public isn't the only ones who doubt the Prince of Wales because his own parents feel the same way. Queen Elizabeth II and Prince Philip reportedly regarded their son a "loose cannon."

Prince Charles gets angry quickly, has given to his own tantrums, is driven by his zeal to "make his mark" by doing various initiatives and causes that the monarch and the Duke of Edinburgh "believe teetered dangerously on the brink of quackery."

There was a period of tension between the trio to the point that Prince Charles and Prince Philip only communicated through writing. The two gentlemen would reportedly disagree loudly that one would suspect there was a fight taking place.

According to Penny Junor, Prince Charles wanted a real man for a son but got a "sensitive child."

"I think what Prince Philip wanted in a son was a man in his own image. A man's man, a rough tough outdoorsy real alpha male," Junor said. "And what he got in Charles was a really sensitive child."

To make the matter worse, Prince Charles didn't have a warm relationship with the monarch, too. Queen Elizabeth II was busy with her role as the monarch and Head of the Commonwealth that she didn't have time to bond with her eldest son.

"The Queen, to be fair to her, was being Queen," Junor said about Prince Charles and Queen Elizabeth II's relationship. "For most of Charles' childhood and the rest of his life, she was on a pedestal and he did not have a warm and cosy relationship with his mother."

Prince Philip and Queen Elizabeth II are concerned about Prince Charles taking over the throne. They reportedly fear that he would do the same mistake that King Edward VIII did when he abdicated the throne to pursue his romance with Wallis Simpson.

In Tom Bower's book "The Power, Passion and Defiance of Prince Charles," Prince Philip and Queen Elizabeth wanted to live longer to keep Prince Charles from the throne. In this way, the Prince of Wales will "have little opportunity to damage the monarchy."