The festivities will begin from Christmas Eve morning at the monarch’s Sandringham residence. According to Hello! Magazine, Christmas for the royals follows a strict timetable rather than being a relaxed holiday.

Royal author Robert Jobson said there is an unspoken rule for guests not to arrive late, adding that there is no grace period. He explained that after completing the unusual custom dating back to the reign of Edward VII, where guests are weighed on antique jockey scales, the schedule becomes tightly managed.

Guests then change for a formal lunch served by royal staff in the dining room. After lunch, most family members take part in an afternoon walk, which is one of the few moments when the timetable becomes slightly relaxed. Even then, they are expected to return by 5pm for afternoon tea.

Royal watchers also catch a glimpse of the family on Christmas morning as they travel to and from St Mary Magdalene Church. However, Jobson noted that many people do not realise the King and his family attend a private church service earlier in the morning, away from cameras and onlookers.

Jobson added that this year’s Christmas holds special significance for the royal family, saying the year has ended on a positive note for the King and that encouraging news about his health has lifted spirits within the family.

Those expected to attend include Prince William, Kate Middleton and their children Prince George, Princess Charlotte and Prince Louis. Prince Edward and Sophie are also expected with their children.

Princesses Beatrice and Eugenie are likely to attend, while their parents Andrew Mountbatten-Windsor and his former wife Sarah Ferguson are not invited.

Prince Harry, Meghan Markle and their children Prince Archie and Princess Lilibet will also be absent from the celebrations.