Britain's King Charles III has decided to adjust plans to inspect soldiers during the annual Trooping the Colour parade next month by opting for a carriage rather than a horseback inspection as he continues with his cancer treatment, Buckingham Palace indicated on Thursday.

The 75-year-old's participation in the ceremony, held on the second Saturday of June to commemorate the monarch's birthday, has been confirmed even as it emerged that his daughter-in-law – also undergoing preventative chemotherapy after her cancer diagnosis – will not be participating in one of the customary prelude events.

Kate Middleton’s role at the Colonel’s Review, scheduled for June 8, will be taken over by a military official instead as it was confirmed that the Princess of Wales will not be resuming her royal duties in time for the event.

The official birthday ceremony of the British Sovereign, scheduled for June 15, is marked each year by a military parade and march past known as Trooping the Colour or the King's Birthday Parade. It traditionally sees all the frontline members of the royal family gather on the balcony of Buckingham Palace to greet the crowds.

Last year, the King inspected troops from horseback during the ceremony that followed his coronation in May. This time, according to palace reports, he will conduct the review seated in an Ascot landau carriage with wife Queen Camilla.

Charles has returned to public-facing duties in recent weeks after receiving treatment for an undisclosed form of cancer, a diagnosis made public in February. Last week, Prime Minister Rishi Sunak announced that he had requested the King to dissolve Parliament as he called a snap summer General Election for July 4.

The ceremony of Trooping the Colour is believed to have been performed first during the reign of King Charles II in the 17th century. In 1748, it was determined that the parade should mark the official birthday of the British Sovereign, becoming an annual event when George III ascended the throne in 1760.

Historically the primary role of a regiment's "Colour" was to provide a rallying point on the battlefield, which was important because without the forms of communications available to troops operating on a modern battlefield it was all too easy for soldiers to become disoriented and separated from their unit during conflict.

For soldiers to recognise their Regiment's Colour, it was necessary to display it; this was accomplished by young officers marching between formed-up ranks of soldiers with the "Colour" held high, which is the origin of the term "trooping". What is today a great ceremonial spectacle began life as a vital wartime parade, the British Army noted.

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