Mr Quinn told The Mirror: “Sarah and her daughters Beatrice and Eugenie have tried to intervene in the feud between William and King Charles and Harry and Meghan.”

“They’ve tried to calm the situation and persuade Harry that he’s had his say and he doesn’t need to stir things up any further, but Harry was never likely to pay much attention largely because his feud with the Royal Family has become a key part of what makes him tick.”

In recent weeks, Sarah Ferguson has made several public appearances, including at the recent Cannes Film Festival in France. Furthermore, earlier this year she told PEOPLE magazine that a key part of maintaining family relationships was “forgiveness”.

She explained: “I think family unity is key… I think the key to life is that we all support each other. And also forgiveness is a great thing. I think forgiveness of yourself and forgiveness of others.”

Mr Quinn commented: “We know that Harry’s deepest upset concerns not just his lack of relationship with George, Charlotte and Louis, but also his own children’s lack of a relationship with their cousins.

“Harry and Meghan would love to get round the problem – they would love it if the cousins could meet regularly and have a positive relationship as they grow up, but they cannot see a way to do it while they themselves, Harry and Meghan, are estranged. Harry has said that he hopes the cousins can at least be friends as adults.”