When Miuccia Prada and one of the US vice-presidential candidates both want you to wear the same kind of jacket, you’ve got to think the universe is trying to tell you something, right?

Miuccia Prada has reigned over the fashion world for four decades, because she has a flawless instinct for what looks stylish rather than just trendy. Occasionally, she will put out a collection in which her taste feels a little off-key, and six months later the rest of the world catches up with her and you realise that, no, she wasn’t wrong; she was just ahead of her time. When Mrs P says we should wear barn jackets, as she did at Prada in February, we should probably wear barn jackets.

And then there’s the fact that a vote for barn jackets is a vote for the Harris-Walz campaign. Tim Walz’s normcore centrist dad energy has given the Democrats a boost. Voters like him and trust him, which is low-key astonishing for a politician these days. His clothes – and I use that word deliberately because the whole point is that it’s not a look, or a style, it’s just his clothes – are part of it. He looks like a nice guy. Along with jeans, plaid shirts and baseball caps, a barn jacket is one of his signatures.

But what is a barn jacket? I don’t know that I had ever heard the term, until recently. An Americanism, I guess. But I’ve seen the jacket, and you have too. Carhartt makes one it calls the OG Chore Coat, and you have definitely seen this jacket, or versions of this jacket, around.

A straight boxy jacket in heavy-duty cotton, maybe waxed, with a simple corduroy collar, hard-wearing snap buttons and patch pockets. The lining is probably checked. It should be hip-length, so that your hands can rest snugly into the bottom pockets as you walk, which is how they were worn on the Prada catwalk, where they were styled with fancy skirts and kitten heels. The style owes a lot to the Barbour jacket, but it’s a bit more down on the farm than country house weekend party. Uniqlo has a version called the Utility Short Blouson, which comes under menswear but looks great on anyone.

The charm of the barn jacket is that the vibe is walking-the-dog nonchalance, but the silhouette is kind of elegant. You will notice that it doesn’t have a hood. A hood would spoil the whole look, I’m afraid. The corduroy collar is what makes it look grownup, and timeless. When you put a hood on a jacket, it changes the mood. Hoods make clothes look assertively modern and youthful, which I guess is why tech bros love them. But the charm of the barn jacket is that it’s not trying to look cool.

This jacket is properly useful. It shares a silhouette with the shacket, in that the boxy shape, the length and the simple collar have a lot in common with a shirt. But it is more versatile than a shacket. A shacket – or one of the more lightweight chore jackets, those French blue classic ones, say – doesn’t have enough heft to be worn over a chunky knit. Put too thick a layer underneath and a shacket looks swollen and bulgy. A bit like you have put your clothes on in the wrong order, which is never a good look. A barn jacket is more structured, and looks at home over a chunky sweater. But you can have fun with it, too. It looks good if you take it a bit preppy. Think of it like a blazer and try it with a short skirt and ballet flats, or dress it up with a crisp shirt and pearls.

Let’s be honest here: the barn jacket may not feel dazzling, in the way that a fancy dress or a shiny pair of shoes might. But true luxury is not having fancy, shiny things; it is having really nice versions of what you use, wear and touch every day. A jacket that is properly useful, but also visually pleasing, is worth its weight in gold. And you don’t have to take just my word on that.

Hair and makeup: Sophie Higginson using Davines and Charlotte Tilbury. Styling assistant: Sam Deaman. Model: Meja at Milk. Jacket: £155, glassworks.com.Shirt: £100, sezane.com. Jeans: £45.99, reserved.com. Scarf: £49, johnlewis.com