Prince Harry and Meghan: Will they or won’t they, and will we care?

From the Sussex perspective, a picture would be a sign of their legitimacy as part of the family. But you can also imagine Palace officials worrying about how such a photo might be used. They don’t want to see it boosting jam sales in Montecito.

David Yelland, former editor of the Sun and presenter on BBC Radio 4’s When It Hits the Fan, says “the politics around that photo are so complex that it almost certainly won’t happen”.

“The photo we really want to see is with the grandchildren,” he says, but he thinks there would be too many arguments about who was in charge of the picture and how it was set up.

“You start to think about the negotiations between the two sides. Who stands where? Is Meghan in the photo? Where’s the King? Is Camilla going to be in the photo?

“It would be easier to get a photo of Putin and Trump together after a meeting than it would be to get photos of these people in the same room at the same time,” Yelland says.

Even without a photo, a meeting seems likely if the children do come to the UK, not least because King Charles, with his own health challenges, would want to see his grandchildren.

Prince Harry will want to reconnect with his family on his mother’s side too – and there has been speculation about a stay at the Spencer estate at Althorp.

That would also mean the possibility of a poignant visit to the grave of Princess Diana, bringing his children to the island burial site of the grandmother they never had a chance to meet.