King Charles Gives Prince Harry the Silent Treatment After Committing 'Cardinal Sin' of Shading Queen Camilla

Prince Harry rushed to the U.K. after King Charles was diagnosed with cancer, but after the monarch skipped his son's Invictus Games event in May, rumors began to spread about the status of their relationship.

"When Harry branded his stepmother Camilla a 'villain' in his book and revealed that both he and William initially begged their father not to marry her, Harry committed what Charles regards as a cardinal sin," Christopher Andersen told an outlet after a source claimed the duo aren't in communication.

"No one disses Camilla in royal circles and gets away with it – not even a son of the king," Andersen warned.

In Spare , Harry painted Camilla as "wicked," and royal experts believe the project took a toll on their bond.

"I think Charles could forgive Harry for some of the trouble he’s caused – including bailing on the monarchy … slamming his brother William for bullying behavior and suing for royal protection when visiting the U.K.," Andersen continued. "But Charles is having a hard time forgiving Harry for taking what he sees as gratuitous potshots at his beloved Queen Camilla."

"This still remains a thorn on the king’s side," he added.

Despite the royal expert's observations, sources claim Harry's legal battle for personnel drove a wedge between the pair.

"He gets 'unavailable right now,'" a friend told a publication. "His calls go unanswered. He has tried to reach out about the King's health , but those calls go unanswered too."

OK! previously reported an insider claimed Harry will need security while in the U.K. despite losing his lawsuit.

“The threat is very real. He needs protection. The idea that the security forces wouldn’t allow anything to happen is a very glib dismissal of the reality of the threat the family faces," a source told an outlet.

Due to Harry leaving the royal fold, the Duke of Sussex would have to give the government 28 days' notice when he travels to his native nation . In the U.K., there are strict firearm regulations, and only specialty-trained members of law enforcement are allowed to carry guns.

“Why would he bring his wife and children back to the U.K. if they are not going to be protected ? The duke needs protection, they need protection," a source said. "The threat level hasn’t changed since he stepped back from the royal family, if anything it has got worse because of the tabloid campaign against him and his wife.”

Never miss a story — sign up for the OK! newsletter to stay up-to-date on the best of what OK! has to offer. It’s gossip too good to wait for!

Over the years, Harry expressed his concerns about bringing his family to the U.K., as there has been a rise in extremist groups.

“The fact that there is even any debate around (Harry’s) security is unbelievable when you look at the situation. The late queen made it really clear [at the Sandringham Summit] that she wanted him and his family protected ," a source noted. "She intervened to allow Andrew to keep his protection. Why is it impossible for his dad not to do the same for Harry? If the king wanted, he could do this for his son.”

Andersen spoke to Fox News Digital .

Sources spoke to People .