The rules of Christmas fashion? Anything goes – but the paper hat is non-negotiable

Christmas is not the time for understated chic, so I’m all-in for sequins, glitter, velvet and heels

There is a scene early on in Spencer, Pablo Larraín’s cinematic fable starring Kristen Stewart as the unhappy princess trapped inside a chilly Christmas castle, in which Diana’s wardrobe for the festivities is wheeled on a rack to her suite. There are gowns for dinners, suits for lunches, a hat for church, tweed for outdoors. Sally Hawkins, playing Diana’s dresser, groans and puffs under the weight as if she is dragging a grand piano.

We mere civilians don’t tend to sit by the tree in Chanel skirt suits. We do not risk a diplomatic incident by being insufficiently groomed. (“But madam … your hair isn’t set”, Diana is admonished.) But that doesn’t mean there are no rules. For most of us the rules of Christmas dressing come in the form of tradition or ritual. Or they are phrased in terms of manners, perhaps, or couched in the language of getting into the spirit. If everyone around your table is expected to put the idiotic paper hat that falls out of their cracker on their head – even if its completely the wrong colour for their outfit – that’s a rule, every bit as much as wearing the correct tiara.

This year, I am all-in for festive fashion. For any outdoor urban seasonal activity – gift shopping at a Christmas market, frankly even just a take-out hot chocolate in a red cup – you will find me channelling a strong Pushkin vibe in plush white knitwear and tight-laced boots. No matter that I’m in London not St Petersburg, nor that I haven’t set foot on an ice rink since the 20th century. If there’s anything remotely Christmassy at the cinema, you can find me queueing for popcorn in black velvet and my best Wolford tights, dressed as if for a box at the ballet.

Whether it’s tartan pyjamas or novelty sweaters, the clothes we wear at Christmas would look eccentric at any other time. Christmas, soundtracked by carols and scented with gingerbread, binds us for a few days to a genteel Victorian jollity at odds with 21st-century life. So our Christmas Day outfits, with their velvet and ribbons and feathers and textured knits, are the Sunday best of modern life.

And even if you love Christmas as much as I do, there is no denying that it is a demanding time of year. Christmas Day is a long day. If you have children, it gets going at warp speed while it is still dark outside. If you are cooking, the day can feel like a to-do list that lasts till teatime. You are torn between wanting to look glamorous and the urgent need for fresh air; between the lure of the afternoon movie and the scatterings of wrapping paper and satsuma peel. And someone needs to put the book tokens somewhere safe and do we have any more AA batteries?

With fashion, as with the rest of Christmas, the best way to stay calm is, counter-intuitively, to embrace the chaos. Glittery tights with a sequin skirt? Absolutely. Pyjamas with high heels and jewellery? Why not. This is not the time to go for understated chic. A fitted little black dress and high heels is hopeless for a day when you need to be able to duck swiftly under the kitchen table to retrieve the crucial new Lego wotsit before the dog eats it. Flats and comfortable clothes, jazzed up with colour and sparkle, seem to me a practical choice. But what do I know? Christmas is different behind every front door. Except that everyone, everywhere has to wear that ridiculous paper hat, right?