The future Queen has only made one public appearance, at Trooping the Colour in June, and her future engagements remain unclear as she is said to attend events when she is able to do so and is given the clear by her medical team.

Mr Burrell added that William mostly enjoys being at home with his family and not being “surrounded by staff and household”.

And he said that’s what differentiates them from other royals, the fact that they want to keep their family core as strong as possible before the “burden of state comes their way”.

The former royal butler explained: “That’s what William enjoys the most, enjoys coming home, enjoys being with his family and not surrounded by staff and household.

“They do spend a lot of time just the five of them by themselves and allow staff to do jobs when it’s necessary.

“It’s different with William and Kate, they want to be a family for as long as they possibly can, before that burden of state comes their way.”