The King’s “lifelong aspiration” is to visit all 56 Commonwealth nations but its ever-expanding membership – and doctor’s orders – have thwarted his efforts.

Charles spoke about his ambition to travel to around a dozen countries missing from his list during a dinner he hosted with the Queen for Commonwealth leaders.

In a speech to those attending the Commonwealth Heads of Government Meeting (Chogm) in Samoa, the King said: “It remains a lifelong aspiration to have visited all the countries of the Commonwealth – although nowadays it seems to be a race against our happily increasing numbers – as well as doctor’s orders.”

On his final night in Samoa, Charles spoke warmly of his affection for the family of nations, saying: “The Commonwealth can surely be a source of hope.”

He added that while “dark clouds gathered”, international challenges required international solutions and that “dialogue and discussion” was the way to achieve peace.

The King’s clothing reflected Samoa, as he wore a Red Sea rig dress shirt with detail from the Samoan School of Fine Art while the Queen wore an embroidered blue tunic and palazzo trousers by Anna Valentine, with diamond earrings.

Charles and Camilla in Samoa – Day Six
Charles and Camilla attend the Commonwealth Heads of Government reception and dinner in Samoa(Aaron Chown/PA)

Charles said in his speech: “As we look from this idyllic place across the world, dark clouds have gathered over many regions, but the Commonwealth can surely be a cause of hope and healing…

“International challenges on such a scale call for international solutions, through dialogue and discussion, for that is where, eventually, peace resides.

“The sheer scale and diversity of Commonwealth membership, spanning the entire globe and embracing more than one-third of the human race, gives us the understanding, the credibility and indeed the clout to play a full role in promoting and protecting peace and prosperity.”

The event for the King, who has been receiving treatment for cancer since early in the year, was his only evening engagement of his nine-day tour of Australia and New Zealand.