The British royal family’s Megxit debacle is largely due to Prince Harry’s failure to adequately prepare his partner, Meghan Markle, for life as a member of the tradition-bound family.

Prince Harry and Meghan Markle, according to royal expert Robert Jobson, author of “Prince Philip’s Century,” were both to blame for the so-called “Megxit.” The duke, however, bears most of the blame.

“It’s a combination of Harry and Meghan’s fault,” Jobson told Page Six. “Mainly Harry’s fault for not explaining it to her properly.”

“He’s not the sharpest guy, but maybe he didn’t want to explain it. It’s hard work being a member of the royal family. People think it’s not but it is. It’s not glamorous and maybe she didn’t fancy that after at all.”

Meanwhile, he believes Harry’s lack of guidance contributed to Meghan’s lack of knowledge of how The Firm operated when she first joined the royal family.

He said that the mother-of-one seemed to be oblivious to their social hierarchy and struggled to accept it.

‘When she saw that she had the little house and William and Kate were the number one couple she probably didn’t understand that and thought, “Well we can do better than this and start commercializing the royal family,” well frankly that’s not acceptable.’

‘I blame Harry really because he knew the story but he wanted his cake and to eat it and you can’t do that.’

Jobson didn’t quite absolve the Duchess of Sussex of responsibility for the couple’s inability to succeed in the royal family, claiming that she should have taken greater interest in what she was getting herself into.

“It’s up to you to do your own homework if you want to marry into a prestigious family.

Meghan had little excuse for not understanding how it operated, according to Jobson, since the Palace appointed Samantha Cohen, a part of the Queen’s personal staff, to assist her in learning the details of becoming a Duchess.

The royal household is all about “service and helping others. It’s not to do with helping yourself. I’m afraid that’s what’s happened here. I blame Harry really because he knew the story but he wanted his cake and to eat it and you can’t do that. ”

The pair officially stood down as senior royals on March 31, 2020.

”After many months of reflection and internal discussions, we have chosen to make a transition this year in starting to carve out a progressive new role within this institution,” the pair said in a statement at the time.

“We intend to step back as ‘senior’ members of the Royal Family and work to become financially independent, while continuing to fully support Her Majesty The Queen.

“It is with your encouragement, particularly over the last few years, that we feel prepared to make this adjustment.

“We now plan to balance our time between the United Kingdom and North America, continuing to honour our duty to the Queen, the Commonwealth, and our patronages.

“This geographic balance will enable us to raise our son with an appreciation for the royal tradition into which he was born, while also providing our family with the space to focus on the next chapter, including the launch of our new charitable entity.

“We look forward to sharing the full details of this exciting next step in due course, as we continue to collaborate with Her Majesty The Queen, the Prince of Wales, the Duke of Cambridge and all relevant parties. Until then, please accept our deepest thanks for your continued support.”

In the meantime, royal biographer Anna Pasternak, author of “The Real Wallis Simpson: A New History of the American Divorce Who Became the Duchess of Windsor,” recently predicted that the Sussexes’ “feud” with the royal family could lead to the monarchy’s demise.

“I’m not 100% sure that we will see Charles ascend to the throne,” she told Vanity Fair for its May cover story. “The Sussexes have sparked something so fundamentally incendiary in this country that it is changing the face of Britain, and I think the monarchy as an archaic institution may well topple.”