On Wednesday, she will hold the last Christmas event at Buckingham Palace before she heads to Sandringham until February – a traditional "all the trimmings" lunch for her extended family, typically between 40 to 50 people.
For this cherished occasion, held in the Marble Hall, three large fir trees are dressed in ornate garlands and "crown and carriage" ornaments. Attendees are seated at round tables and pull crackers before being served a Sandringham-bred turkey lunch.
"The point of the Palace Christmas lunch is a way for The Queen to thank the extended Royal Family for all their help to her during the year," says Hugo Vickers, author of biographies of Queen Mary and the Duchess of Windsor.
The pre-Christmas lunch is one of the only occasions in the royal calendar when the monarch's extended family are all gathered together, so it is a rare chance for the Queen to celebrate with those who do not receive an invitation to spend Christmas with her and senior royals at Sandringham. In 2017, the Duchess of Cambridge pulled a cracker with Prince Charles, put on the paper party hat found inside and read out a joke.
While Prince Philip attended the lunch last year, it is unlikely that he will make the trip to London this year. At the age of 98, he is believed to not be in the best of health – one reason why Christmas Day at Sandringham will be extremely important to the Queen this year.
Since his retirement from public life in 2017, Prince Philip has spent most of his time at Sandringham. While the Queen is away, he lives at Wood Farm, a modest cottage on the 20,000-acre Norfolk estate bought by Edward VII in 1862. The Duke of Edinburgh now spends his days there painting, reading and entertaining friends and family.
But on Christmas Day, he will join the Queen at Sandringham House, along with their extended family. The Duke and Duchess of Cambridge will come over with their children from their home in nearby Anmer Hall. Conspicuous by their absence will be the Duke and Duchess of Sussex and baby Archie, who are currently on a six-week break from royal duties and have decamped to an undisclosed location abroad to spend Christmas with Prince Harry's mother-in-law, Doria Ragland.
Large family gatherings used to be held at Windsor, a tradition that stopped many years ago – to the relief of all, a now-deceased courtier once told me. The pattern for Christmas, laid down by the Queen after she came to the throne in 1952, goes like clockwork.
The family waits until Christmas Eve to put the finishing touches to the Sandringham tree, a 20ft fir from the estate that takes pride of place in the White Drawing Room.
Then, the family follow the German custom Heiligabend Bescherung, meaning "Christmas Eve present exchange", one that can be traced back to Queen Victoria and Prince Albert. The presents are laid out under the Christmas tree – another German tradition, introduced by Queen Charlotte in the 18th century.
Like the Queen, the Royal Family don't go in for lavish presents to each other, not least because there are so many members of the family present. Instead, they prefer to give jokey stocking-fillers. Novelty mugs are a particular favourite.
The Queen herself is keen on giving practical presents. In Vickers's book, The Quest for Queen Mary, writer James Pope-Hennessy describes the Queen's present to her uncle and aunt, Prince Henry and Princess Alice, the Duke and Duchess of Gloucester, in the late 1950s: "When we had sat down to tea," writes Pope-Hennessy, "Princess Alice remarked on a rather unpleasant Formica tea trolley which runs on rubber wheels and opens into a table.
"What a nice trolley that is, Alice."
"Yes," [she said] smiling. "It's the very latest thing. It won't burn or stain or scratch and it folds up. It was Lilibet's [the Queen's nickname from childhood] Christmas present to us. Wasn't it kind of her? Terribly expensive, though."
"How much?"
"£17. It came from Fortnum and Mason."
The Duke looked at it solemnly and, with the air of a man making a decisive announcement, the product of much thought, said: "Most things that come from Fortnum and Mason are terribly expensive."
The Queen particularly appreciates handmade presents. In Vickers' book about Queen Mary, James Pope-Hennessy finds himself playing Scrabble with the Duke of Gloucester on a turntable.
"My son made one for the Queen for a Christmas present, copy of this," remarked Prince Henry. "Cost me two bloody quid, though. Everything they do at that school [Eton] costs money."
After the exchange of presents, there is a formal black-tie dinner on Christmas Eve, where the ladies wear their smartest jewels.
On Christmas morning, the Royal Family attend that Christmas service at St Mary Magdalene Church and then sit down to lunch in Sandringham's dining room. The vast space is painted green in emulation of a room Queen Mary admired in a castle in Braemar, Scotland. It is designed in a light, classical style, with tapestries by Goya, a present from King Alfonso XII of Spain in the late 19th century.
The large dining table comfortably accommodates 24 people – big enough for the extended Royal Family. It is laid out with the Queen's favourite placemats of hunting scenes, which are replaced by more lavish settings when Prince Charles takes Sandringham for several weekends a year.
The Royal Family eat a traditional Christmas lunch, rounded off with a viewing of the Queen's Christmas Message at 3pm. For the rest of the day, life revolves around the favourite room of the Queen and Prince Philip, the Saloon. It's really the hall, but it's set up like a drawing room, with Old Masters on the walls, a roaring fire and an "Elizabeth R" cushion on the sofa.
Sporting life is important at Sandringham. While the Queen is there – and she will usually stay throughout January in the build-up to February 6, the anniversary of the death of her father, George VI, in 1952 – she will visit the Royal Stud, founded by the Prince of Wales in 1866.
On Boxing Day, the traditional shoot takes place, with the Queen acting as a picker-upper of pheasants with her gundog. As one guest, another courtier, told me: "It slightly concentrates your mind when you're shooting and you know Her Majesty is standing behind you, seeing how good, or bad, a shot you are."
