After a medical annus horribilis, the King will unite his family at Sandringham for their biggest gathering yet. Anna Pasternak reports on the tensions, traditions and fallouts that will shape the royal festivities.

King Charles is pushing the boat out for Christmas this year, inviting a whopping forty five family members to join him and Queen Camilla at Sandringham in one of the biggest regal festive jamborees of recent years. Who can blame our staunch monarch for wanting to draw his loved ones close at his Norfolk residence to raise a glass after his medical annus horribilis? He has spent the last gruelling year battling an undisclosed form of cancer, along with his daughter-in-law, the Princess of Wales, who is also recovering from chemotherapy treatment.

It will cheer the country’s flagging spirit to see Charles and Kate join their wider family on the royal walkabout as they file to St Mary Magdalene Church at Sandringham on Christmas Day. It is likely that part of the intention behind Charles’s lavish shindig is that he wishes to thank and honour his relatives who have stepped in and up during the last year of straightened circumstances, propping up such a slimmed-down monarchy. The peerless Princess Anne, her husband, Vice Admiral Sir Timonty Lawrence, along with Anne’s children and grandchildren will be present, along with the Duke and Duchess of Edinburgh and their children. Nothing new here because they are royal regulars on the Sandringham Christmas circuit.

However, this year, what is endearingly modern is that Charles and Camilla — like most of the country — will, as the result of divorce, be gathering a blended family for Christmas. Camilla, who had to forgo spending Christmas Day with her children and grandchildren for two decades when the late Queen was alive, can, as chatelaine of Sandringham, finally include her own family. Her son Tom Parker Bowles, will be part of the house party, along with his children, Lola, 17 and Freddie, 14, while Camilla’s daughter, Laura Lopes, is also expected to attend with her husband and three children. It is believed that Camilla’s sister, Annabel Elliot, is also invited.

Similarly, as in most families, fall-outs and tensions preclude certain clan members being included but unless you are royal, these uncomfortable exclusions do not make the front page. This year, the absence of the Duke and Duchess of Sussex and their children, Archie and Lilibet, hasn’t raised so much as an eyebrow. The world would only sit up and scream if they were attending.

The real chorus of condemnation is once again howling in Prince Andrew’s direction. Originally, he was invited with the Duchess of York to join the family for the whole festive shebang. I felt happy about this for Sarah — and was equally delighted by Charles who invited her to Sandringham last year — after her decades in Yuletide exile. I always thought that it was cruel and positively Dickensian that she was hidden away in a cottage on the estate, while her husband and children joined the party at the main house purely because Prince Philip disapproved of her. Shouldn’t we prioritise forgiveness and generosity of spirit at this Holy time?

However, the latest scandal involving Prince Andrew and his links to alleged Chinese spy Yang Tenbo, whom Andrew twice invited to Buckingham Palace in the past as part of his hapless entrepreneurial schemes, has meant that stoic Fergie has taken the heavy-handed hint from Palace insiders that she and Andrew should quietly back away from the family Christmas so as not to further embarrass King Charles. Sarah, who says that she “absolutely adores” the King, tickled that he still calls her “Fergie,” is resolutely loyal. I’m saddened that just as she had made it back into the royal fold, because of Andrew, “the sad man” that she unwaveringly supports, she is forced back into the permafrost of a non royal Christmas. As head of the Church of England and Defender of the Faith, shouldn’t Charles be more inclusive to his brother and ex-sister-in-law, instead of bowing to international optics?

While we might envy the full panoply of staff who will make Sandringham sing and thrum with life this Christmas, entertaining this internecine lot hellbent on monarchical survival will not be without tears and tantrums. If no longer, tiaras. The late Duke of Windsor described life behind the turreted façade of the royal households eloquently: “Christmas at Sandringham was Dickens in a Cartier setting.” I am sure that the Queen will not don a tiara along with a paper crown for the black tie dinner on Christmas Eve. The King’s great grandmother, Queen Mary, insisted at Sandringham that “if the king were present they put on garter ribbons, tiaras and diamonds for every family dinner even without guests,” according to Mary’s aide, the Hon Margaret Wyndham.

Camilla will certainly soften the starchier traditions with her maternal warmth and down-to-earth approachability. Yet even if the emotional sterility of the past is banished, it remains that Sandringham House is an ugly, and possibly spooky, dwelling. The writer James Pope-Hennessy described it as “a hideous house with a horrible atmosphere in parts, and in others no atmosphere at all. It was like a visit to a morgue.”

Unlike his mother, our late Queen Elizabeth, who had no particular interest in food or interiors — she favoured electric bar fires and tupperware with cereal plonked on the breakfast table — King Charles relishes comfort at his royal residences where he hosts with panache. Like his great uncle, the Duke of Windsor, Charles oscillates between parsimony and lavish excess. Prince Harry recalled in Spare how Charles is always switching the lights off at Highgrove yet any gloaming at Sandringham will be offset by glittering tablescapes, delicious organic food and the finest wines.

In a nod to their German roots, the royal family open their presents which are laid out on trestle tables on Christmas Eve at tea time. God forbid, as Princess Diana innocently did at her first Sandringham Christmas, to disapproving sniggers, that you buy anything chic or expensive. Her in-laws, in true aristocratic style, were horrified when she gave them carefully selected cashmere jumpers. The royals favour lavatorial humour and cheap jokey gifts. Anything more sophisticated is considered the height of vulgarity. Kate quickly cottoned on that the perfect gift for the late Queen was a jar of home-made chutney. Meghan’s Riviera Orchard jams would have made ideal offerings if she had made the royal Christmas cut.

The regal clan will sit down to lunch at 1.15 pm sharp on Christmas Day — according to Prince William “all in one room” but “normally spread out.” Amidst the exhausting noise levels that 45 members of this privileged clan will make, my guess is that it will be impossible for King Charles to ignore the silent ghost of Christmas family members not present. Tensions between Charles and Andrew were heightened prior to the Chinese spy brouhaha over Andrew’s refusal to vacate Royal Lodge. The pater familias not just of the household but of Britain always has to make a choice between kin and country. Like his mother, King Charles puts duty first — even on Christmas Day.