Following his diagnosis, the King took a three-month hiatus from his Royal engagements to focus on his recovery. He made a successful comeback in April, and those close to him have remarked on the prevailing sense of hope due to the positive response to his treatment, reports the Express.

They shared with the publication that although the monarch is “not yet out of the woods”, there is “great optimism” and the treatment has progressed “better than anyone would have thought”.

The insiders noted: “It wasn’t like he was totally broken and nor are we totally out of the woods yet as treatment continues. Treatment has gone better than anyone would have thought even in their most optimistic thoughts.”

An individual in the King’s inner circle commented: “The sun wasn’t shining in February but it is shining now”. Charles has been beaming throughout the summer, attending numerous events and garden parties as he continues his treatment.

On Monday, the King was seen at the gates of Balmoral, inspecting the Balaklava Company, 5th Battalion, The Royal Regiment of Scotland. This ceremony signified the official welcome of the monarch to the Aberdeenshire castle, where he and the Queen will spend their summer holidays with other members of the Royal Family.