“And they’d love to be in the UK, I think up to half the year with this rival court, and then it’s going to carry on into the next generation.” He added: “And Archie and Lili, when they’re teenagers and young adults, I predict will make life a misery for George, Charlotte and Louis.”

Mr Dolan also urged King Charles to counteract the threat by “scaling back” operations and turning the monarchy into a “lean, mean fighting machine”.

“Constitutionally, I think he’s been a good king, and he’s a kindly and intelligent man, very ethical as well,” he said. “But he’s got to modernise the monarchy.”

A spokesperson for the Duke and Duchess of Sussex described the comments as “deeply distasteful”.

They said: “There is a fundamental difference between criticising public figures and choosing to demonise two young children who have done absolutely nothing to warrant it.”

“To speculate that Prince Archie and Princess Lilibet will one day ‘make life a misery’ for their cousins is an extraordinary and irresponsible thing to say about children.

“We are genuinely disgusted by these comments. Whatever views people may hold about the Duke and Duchess of Sussex, children should never be dragged into adult disputes or portrayed as future antagonists for the sake of a provocative soundbite.

“Most people would recognise that as a line which simply should not be crossed.”