Britain marks King Charles III’s official birthday with the Trooping the Colour ceremony in London. Multiple outlets report that the event is held on Saturday, 13 June, and features the King taking part in the annual parade that celebrates his birthday with a public display by the armed forces. Coverage also notes that crowds gather in central London to watch the ceremony. Several outlets provide live viewing instructions or “watch live” coverage, indicating that the parade is broadcast for audiences who cannot attend in person. One source specifically frames the day as the King celebrating his birthday at the event, while another highlights the official nature of the occasion. France 24 emphasizes the public atmosphere in central London, describing people assembling to witness Trooping the Colour. Across the reports, the central points remain the same: the ceremony is Trooping the Colour, it is tied to King Charles III’s official birthday, and it takes place in London on 13 June with substantial public participation.