A nine-day royal Caribbean tour ended with a dinner for Commonwealth presidents and prime ministers on Tuesday.
The banquet was the final event of a trip that took in a state visit to Guyana, a stay in the Bahamas and a concluding leg in Antigua for the Commonwealth Heads of Government Meeting (Chogm).
Hosting the dinner, the King joked about the moment he was caught in a downpour, quipping he would “provide an umbrella for you all”.
Footage of the soaking had been seen around the world.
It showed Charles raising his arms and calling for an umbrella on Sunday as torrential rain fell moments after he arrived at a cricket stadium for Antigua and Barbuda independence celebrations.
Speaking to launch the summit, Charles said the transatlantic slave trade “fills my heart with horror and my soul with the most profound personal sorrow”, but did not offer an apology.
The King also praised the “leading role” of the Royal Navy in helping to enforce the end of slavery once it had been abolished.
Britain's warships had spent more than a century protecting vessels carrying enslaved people and defending the Caribbean's profitable sugar-producing colonies based on slave labour before that.
Guests at the dinner included Andy Burnham.
Addressing them, Charles praised the Commonwealth, saying: "It is one of the few organisations able to unite countries famous for snow, countries famous for deserts, and, most of all – countries whose citizens are utterly convinced they enjoy perfect weather all year round.
“Although perhaps part of my role as Head of the Commonwealth is to provide an umbrella for you all,” he quipped.
The joke drew laughter in the dining hall and a round of applause.
In more serious moments, he touched on the importance of the Commonwealth as Queen Camilla listened with other guests.
“Ladies and gentlemen, we meet at a time when many of the institutions on which the world has long relied are under great strain, and when it is all too tempting for nations to retreat behind ever higher walls,” he said
"I cannot help feeling that such a world would be poorer, more fragile and, if I may say so, a good deal lonelier and more dangerous.
“Our Commonwealth, I think, offers another path.”
A bespoke cocktail, called the Commonwealth 56, was served at the dinner.
It is a twist on the French 75, made from Antilles Stillhouse Pink Sorrel Hibiscus Gin produced on the hills above the English harbour in Antigua, and a sugar syrup from Buckingham Palace honey.
Diners at the Blue Waters hotel in the capital St John's ate an avocado, green beans, quail eggs and cherry tomato salad, followed by Mahi-Mahi fish with seasonal vegetables.
The meal finished with an Antiguan black pineapple tarte tatin and hand-painted chocolates.
Charles and Camilla will fly home on the ministerial jet Voyager after being waved off by Antigua's governor-general, Sir Rodney Williams and his wife, Lady Williams.
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