The Duke and Duchess of Sussex “crossed the red line” in deciding to walk away from the monarchy, a royal biographer has said, following the announcement that they are to be stripped of their patronages.

Angela Levin said the Queen was a “patient woman” but that she was “devoted to her sense of duty” and the protection of the royal family.

It comes after Buckingham Palace released a statement saying all were “saddened” by the decision, but Harry and Meghan remained “much loved members of the family”.

“I’m not in the least surprised.

“I think there’s been a lot of rumours that the Queen would do this,” Ms Levin told the PA news agency.

“The Queen as we know is devoted to her duty and to her country…she loves her children and being a grandmother.

“But in the end her sense of duty is more important than grandchildren or children or great grandchildren.

“She wants to keep them close as a family, but they cannot push their luck too far.”

Ms Levin said there had been concerns at the palace over how “increasingly escapist” Harry and Meghan had become.

“(The Queen) doesn’t want the royal family’s name to be tainted in that way and this, I think, crossed the red line,” she said.

“She’s a very patient woman, she’s not a micromanager.

“She lets her children and grandchildren do what they want up to a certain extent and when they overstep that, she comes down.”

The announcement comes ahead of a special interview of Harry and Meghan with Oprah Winfrey, which is due to be broadcast in March.

“When senior members of the royal family say too much or say things that (the Queen) thinks are wrong the whole family is affected by it,” said Ms Levin.

“I think she is very concerned about what the interview with Oprah Winfrey will reveal.

“There’s been a lot of publicity saying that it’s going to be a tell-all, no-questions-barred, and I think she’s concerned about how that would be, and she’s got to protect the royal family.”

Asked about the future relationship between Harry and Meghan and the rest of the royal family, she continued: “I think it’s very difficult indeed.”

“I don’t think it will be bonding.

“I think (Harry) is more loyal to his wife.

“He adores Meghan and she is his priority.

“But you can’t have it both ways, you can’t be half in and half out.

“This is one chapter in a very long story, and we don’t know what’s going to happen.

“I hope that maybe this new baby, now that Meghan is pregnant again, will help make some sort of bond, but we shall have to see.”