Former Foreign Secretary David Lammy, who has strong family ties to the Caribbean, has accompanied the King on a number of trips outside the UK.

“He is our head of state. He is amongst some of the most recognisable figures in the world. For a small country like Guyana, the validation of a state visit is huge,” said the Tottenham MP whose father came to the UK from what was then British Guiana and who also has relatives in Antigua and Barbuda. “My mother would forever recall the Queen’s visit in 1996.”

But there was also a recognition of that royal trip jeopardy.

“Knowing Guyana, Antigua and Barbuda as well as I do, he will be overwhelmingly received positively,” Lammy said. “But these are lively democracies in which of course there will be some dissent.”

A transatlantic flight, three countries over nine days and about 36 separate engagements when you’re closing in on your 78th birthday is an intense schedule. It is also a reminder that the King is still dealing with a cancer diagnosis and having regular treatment. Buckingham Palace has reiterated its position that he is on a “positive trajectory”.

Queen Camilla will only accompany the King on the Antigua and Barbuda leg of the visit for Chogm and a number of other engagements, including some around her own areas of interest – literacy and supporting efforts to end violence against women and girls.

The Queen, who will be 80 next July, is known to find the pace and hot conditions of some royal tours gruelling.

This is a trip that comes with potential pitfalls but also the possibility of great reward for the King.

“The King can be an extraordinarily empathetic and in tune figure,” Sir Anthony said.

“He could play a blinder here.”

Additional reporting by Felicity Baker