“I think that he does unquestionably view the way the break has occurred with the Royal Family. Which, as I say in my opinion, is the fault of the Sussexes.
“We know they wanted an apology from the Royal Family for the way they were treated when they were senior working members of it. They certainly won’t get that. But I do think there will be a certain amount of regret.
“The military has been a very important part of his life, and I would have thought it only natural that he would have had a feeling of some regret [not being at Trooping the Colour].
“I think Meghan would be indifferent to a ceremony like Trooping the Colour quite frankly. I have no idea whether she would or wouldn’t actually watch it, but I don’t think it would mean a great deal to her.
“If it had done, she would have managed to carve a position within the Royal Family where she could have been of use.”
Harry and Meghan were last in the UK in May, when Harry was in the country for an Invictus Games event. Meghan only stayed in the UK briefly before the couple headed to Nigeria for their tour of the country.
Mr Fitzwilliams believes that it is unlikely we will see Harry, Meghan, or their children – Prince Archie and Princess Lilibet – on the Buckingham Palace balcony soon.
He said: “I think it’s impossible to imagine Archie and Lilibet on the balcony of Buckingham Palace, or at Trooping The Colour by themselves.
“We will only see them on the balcony with Harry and Meghan and the rest of the family if the rift is solved. The appearance of the Sussexes anywhere is accompanied by a vast amount of publicity. It would overshadow the parade this weekend.
“Trooping the Colour is about the King, first and foremost. Harry and Meghan would bring some form of publicity circus with them.
“You simply cannot have Trooping The Colour where the centre figures are Harry and Meghan. Because it would be ridiculous. Every single time the Sussexes appear, they attract phenomenal amounts of publicity. I’m looking at a period of quite a number of years before they come to a royal event again.”