Former royal press secretary Dickie Arbiter told True Royalty TV that the world was the Duke and Duchess of Sussex’s oyster but they blew it.
He claimed that Prince Harry was content in his role of “spare” in the Royal Family until he met Meghan Markle, who could not accept it.
Mr Arbiter said: “Their world was their oyster and they blew it. “They literally blew it, they had everything, I don’t think everything was what Meghan wanted.
“Harry was the spare and the Cambridges are the heirs, he accepted his role, he was always born to that.
“Until Meghan came along and she could not accept that, she couldn’t accept being in the second row.
“Quite frankly, Harry’s biggest mistake was leaving the army. He should have never left.”
However, Prince Harry fell into the “trap” of being a spare member of the Royal Family according to Robert Lacey.
The royal historian told the Royally Obsessed that the Duke of Sussex and the Duke of Cambridge started life as co-stars.
But as the brothers got older their paths diverged and the Duke of Sussex began to resent his role as spare in the monarchy.
Mr Lacey said: “Harry fell into the same trap as the spares before him. “There is in Britain the tradition of the heir and the spare.
“To start with in life they are co-stars, both of them idolised by the nation and the world. “As early as I say in their childhoods, they became aware of it.”
He added: “Prince William derived a lot of strength from the idea that he would be king, and have great responsibility.