Interestingly, one of the biggest trend stories to come out of the recent autumn/winter ready-to-wear shows did not, in fact, have anything to do with autumn/winter but rather was all about something that is happening this spring/summer. To wit: the return of the jacket.
For there, in front rows from Manhattan to Milan, sat Anna Wintour - a woman who has, in recent seasons, made practically a signature of sporting a full skirt with cardigan - all neatly buttoned-up in a black-and-white polka-dotted Yves Saint Laurent suit (a jacket-and-skirt combo that, not so coincidentally, Carine Roitfeld, French Vogue editor, also owns).
And, lest anyone claim Wintour doesn't put her money where her magazine is, there, too, on style.com, Vogue's cyberspace home-away-from-home, is the jacket, front and centre in the "Top 10 Trends" heralded as nothing less than an "outfit definer."
Meanwhile at rival Harper's Bazaar, it's the number one trend for spring/summer, the item "you won't want to leave home without".
"These are just great investment pieces," says Lucy Yeomans, editor of Harper's & Queen, a magazine that has just produced a supplement dedicated to the businesswoman that features 10 pages of jackets and coats. "They are both directional and versatile, and they make your wardrobe work."
Retailers, too, are on board. "We've bought it very heavily and even the high street is doing it," says Anna Garner, fashion director of Selfridges.
"The one thing to have for spring, without a doubt, is the jacket," says Evelyn Gorman of the Houston boutique Mix to Bazaar.
All of which just underlines the fact that, though every season fashion can propose a turn of the trend, can push a new look or style (for autumn/winter, for example, one of the predominant propositions was shorts), just because designers think something is a good idea does not mean that women will agree. For that, you have to wait until the actual season, to see what has, literally and metaphorically, been bought. (If you think shorts will be big for next Christmas, I have a friend called Santa Claus I'd like you to meet). The jacket has passed both tests.
At Yves Saint Laurent, for example, the Saharan jacket (a variation on the classic, Safari style made famous by Veruschka) was a sell-out in Paris, and a waiting list exists at the Sloane Street store in London for a sister number with a heart-shaped neckline.
Meanwhile, at Christian Dior, John Galliano introduced the reworked "Bar jacket" last season - an updated version of the brand's classic 1947 New Look silhouette, with folds instead of lapels and a bit of a sculpted flare over the hip - in everything from satin to denim.
"I want it to become a feature and strong identity for the house," he says. Apparently, it is working: chief executive Sidney Toledano reports a "double digit sales increase in the category".
And at Balenciaga, where looser, naval styles were the order of the day, a double-breasted, gold-buttoned creation has been photographed practically as many times as there are women's magazines.
"There's a whole rainbow of styles available," says Garner, "which means almost anyone can wear a jacket almost anywhere. These jackets are easy pieces, not over-thought; they are meant to be a finishing part of an outfit, not one half of a match."
Indeed, one of the hallmarks of this renaissance in jacket-wearing, as opposed to its last, 1980s heyday, is the sense of the jacket as a "piece" as opposed to a part of a suit.
"It's kind of a compromise between the business suit and a casual look," says Garner.
As a result, even styles that resemble some of the more classic '80s items, such as Balenciaga's double-breasted beauty, come with softer, unstructured shoulders to avoid that exaggerated, I'm-going-to-smash-through-the-glass-ceiling-if-it-kills-me look.
And, perhaps because today's jackets stand on their own as an element in a wardrobe, and there are as many wardrobes as there are women in this world, there is a version for pretty much any aesthetic or situation.
Aside from the above-mentioned YSL, Dior and Balenciaga offerings, there are cropped, bracelet-sleeved styles from Chloé and Marni, often produced in what Garner terms "organic fabrics" to take the professional edge off; Proenza Schouler's quilted, African-print, boxy-but-uptown looks; Alexander McQueen's shrunken, nipped-at-the-waist Edwardian schoolboy styles; and Valentino's classic belted versions (to name but a few).
As a result, says Yeomans, "a great jacket becomes a great solution. I have one khaki military style I bought recently from Zara that I wore to the BAFTAs with a black satin Missoni pencil skirt, and that I also wear at the weekends with a peasant skirt. To me, it's just the ultimate in easy-to-use items."
Her words are echoed by Natalie Massenet, founder and CEO of internet fashion store net-a-porter.com, who has announced her spring uniform will be "men's-cut blazers and floaty prairie skirts".
And the two are not alone. After all, many women - especially professional women (Ms Wintour aside) - never really took to the cardi-and-cami style. "It's fine in the magazine business, but in a boardroom, or a room full of men in suits, you really want more armour," says Yeomans.
Jackets, you might remember, provide both a psychological and physical boost - by holding you in, broadening your shoulders and creating the optical illusion of a waist, they also bolster your sense of security. You don't have to worry about stomachs pooching out of them, or whether or not your apple/pear shape has been sufficiently disguised. You don't have to worry that someone will mistake you for an over-age Betty Boop.
Perhaps this is one of the reasons, as Galliano says, "women have gone wild for the jacket. It aims not only to enhance but to conceal - just the way clever cutting should."
Men, of course, figured this out long ago - indeed, in many ways, the chino was the male equivalent of the cardigan, and we know what happened to those. There is a reason, after all, that dress-down Fridays were such a short-lived phenomenon whereas the jacket, by contrast, seems to have been around forever (there's also a reason that even during dress-down Fridays, the jacket never really went away; it just ceased to be a part of a suit).
Dior, for one, is betting long-term on the item. "The investment behind the jacket has been significant. We have promoted the jacket in our advertising around the world beginning with Riley Keough and now with Kate Moss," says Toledano.
"We believe very strongly in John's vision. The jacket transcends age: a young woman can wear it as easily as her mother. And, of course, because a jacket is a great separate, it takes on completely different looks depending on what you wear it with. This makes it a staple in any woman's wardrobe and we knew immediately the Dior Signature jacket would be a staple piece in our business."
And for anyone hesitating on the brink of the jacket purchase-precipice, wondering whether it is a worthy investment, and what its future prospects are - worrying that this sudden upsurge in jacket-wearing is a blip, a temporary throw-back to an earlier time that will spark its own quick-twitch backlash - should know that, for autumn/winter, jackets made an even stronger catwalk showing.
Chances are, Anna Wintour's personal orders are already in.
Vanessa Friedman is the FT's fashion editor
