The monarch, 96, welcomed four children with her late husband, Prince Philip. Her first-born, Prince Charles, 73, was followed by Princess Anne, 72, Prince Andrew, 62, and youngest Prince Edward, 58.
The Duke of York has long been considered the Queen’s favoured child, with royal commentator Richard Fitzwilliams claiming Andrew is “someone with whom she’s had a particular affinity”.
But the Queen has considered another one of her sons her favourite child, according to a royal author.
Matthew Dennison claimed the Earl of Wessex, the youngest of the siblings, has “always” been the favourite of both the Queen and the Duke of Edinburgh.
Mr Dennison claimed the Earl, who is married to Sophie, Countess of Wessex, seemed “a bit wet” and “irritating” to many, but was not so to his parents.
He wrote in a new biography of the monarch: “Prince Edward, seemingly a bit wet and a tad irritating to the rest of us, was always his parents’ favourite.
“That became apparent in 1987 when Edward, aged 22, opted out of the Royal Marines when he was just a third of the way through his 12-month basic training course.
“To the surprise of some, Prince Philip did not come down on his son like a ton of bricks.
“He accepted that the Marines ‘wasn’t right for Edward’ – and to this day Edward is grateful for that.”
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“He had all the physical ability to complete his training satisfactorily – indeed well.”
The Earl then dived into arts and theatre, which he had enjoyed during his time as a student at Cambridge University.
But media reports and some commentators have alleged that Prince Edward had an “argument” with his father over the departure from the armed forces.
At the time, the Duke of Edinburgh was Captain General, Royal Marines.
Royal expert Ingrid Seward has previously claimed that the Queen herself felt “initial shock”, morphing into “icy-cold regal displeasure”.
She added in the Daily Mail back in 2017: “Stories soon spread that harsh words had been exchanged between father and son; even that Edward had been reduced to tears by his father’s anger.
“It was a potent image that grew in the retelling.
“The truth was quite the opposite: of all the Royal Family, Philip was in fact the most sympathetic.
“He understood his son’s decision, which he considered a brave one, and supported him fully.”