King Charles III is not slowing down in his royal duties despite experiencing a "very difficult year health-wise," a British news show has heard, as the monarch wrapped up a two-day working visit to Edinburgh in Scotland this week ahead of the general election.

Newsweek's chief royal correspondent, Jack Royston, told Sky News on Wednesday that the monarch was looking "happy and healthy," despite continuing treatment for an undisclosed form of cancer.

Charles' diagnosis was announced in February, after which he was advised by his doctors to considerably reduce his public facing engagements and limit himself to light desk duties to minimize the risk of damaging his health.

The king was given a green light to resume his wider work in April, though his treatment has not yet concluded, with the monarch telling officials at an event that he had finally been let out of his "cage."

On Tuesday, Charles and Queen Camilla began what is known as "Royal Week" in Scotland, which sees the sovereign take up official residence at the Palace of Holyroodhouse in Edinburgh (the monarchy's primary Scottish seat).

During this period, the king receives the keys to the city, and hosts garden parties and investitures. This year, the residency has been cut short, due to the general election in which Brits will elect a new government on July 4.

Despite this, Royston told Sky News viewers that the king's Scottish events held a significant place in the royal calendar.

"There's a huge and very important connection between the royal family and Scotland but it's also a very important year this year because Edinburgh is celebrating 900 years, it's their 900th anniversary," he said.

"[On Tuesday] Charles had the Ceremony of the Keys which are symbolically the keys to the city that are presented to him. He touches the cushion and that kind of symbolizes the king's reign being over Edinburgh and being over Scotland too."

"It's a fantastic ceremony," he continued, going on to add that the king "looked happy and healthy" considering the workload he is taking on during his cancer journey.

"It's great to see him still looking his best, I would say, after a very difficult year health-wise but he is not stopping and he's not slowing down.

"Although he is cutting Holyrood week short this year because of the general election, partly no doubt to avoid presenting a distraction for people but also I think he probably wants to find out the result as we all do and soon he may well be swearing in the third prime minister of his reign."

Newsweek approached Buckingham Palace via email for comment.

The election in Britain is one of the most anticipated in recent years. Pollsters predict a landslide shift from the incumbent Conservative party, led by Prime Minister Rishi Sunak, to the opposition Labour Party, headed by Sir Keir Starmer.

If Starmer were to be elected on Thursday, he would travel to Buckingham Palace soon afterwards to take part in the "kissing hands" process with the king.

The ceremonial gesture links back to days where the new prime minister would be asked to form a government in the monarch's name, and they would then kiss the royal's hand.

Today, no kissing actually takes place. The gesture is considered to have been performed by virtue of the meeting being held.

When Charles became king, Conservative leader Liz Truss was prime minister. She left office after 49 days, just over a month into Charles' reign, whereupon Rishi Sunak took over as leader of the party and was invited by the king to form a government as his second prime minister.

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