The Monarch asked Penelope Knatchbull, Countess Mountbatten of Burma, to take Prince Philip, then 98, for a drive during a crisis summit with the young royals, Ingrid Seward writes.

The knife edge meeting came after the Duke and Duchess of Sussex announced their plans to leave royal life, giving Elizabeth, 94, just ten minutes’ notice, according to biography Prince Philip Revealed.

The book describes how the queen knew they were unhappy but had not been aware of their intention to live “half in, half out” of the royal family, which Philip believed was “impossible.”

Seward writes: “The queen refused to allow their shenanigans to get to her husband.

“So, when she called an emergency summit at Sandringham on January 13, attended by her son the Prince of Wales and grandsons Prince William and Prince Harry, as well as their senior advisors, she asked one of her house guests, Countess Mountbatten, to drive him away from the house at least for the duration of the meeting.

“While they sat in the long library on the ground floor and thrashed out a solution that would allow Harry and Meghan their freedom without bringing the royal family and the Crown into disrepute, Philip remained out of the way.

“Buckingham Palace later released an unusually personal statement from the Queen saying that the family were entirely supportive of Harry and Meghan’s desire to create a new life as a young family.”

The talks were known in the media as the “Sandringham Summit” as they happened on the Sandringham estate, in Norfolk, where the queen traditionally spends Christmas and New Year.

Meghan and Harry had uploaded a detailed plan for how they intended to continue to serve his grandmother while splitting their time between North America and Britain.

Finding Freedom, a biography of Meghan and Harry published this summer, describes how they left the queen “devastated” by announcing the plan to the world without agreeing it with her first.

In her book, Seward writes: “It must have come as a heavy blow for Prince Philip to know that his grandson would be more or less giving up his homeland and everything he cared about for a life of self-centered celebrity in North America.

“Philip knew leaving was not a decision that Harry made lightly and could not grasp exactly what it was about the family firm that made his grandson’s life so unbearable.

“As far as Philip was concerned, Harry and Meghan had everything going for them: a beautiful home at Frogmore, their healthy son, a unique opportunity to make a global impact with their charity work.

“For a man whose entire existence has been based on a dedication to doing the right thing, it appeared that his grandson had abdicated his responsibilities for the sake of his marriage to an American divorcée in much the same way as Edward VIII gave up his crown to marry Wallis Simpson in 1937.”