crolling through the Instagram page of model and Kardashian scion Kendall Jenner, one photo, posted on 28 April, stands out. In this one, she’s not on a Vogue cover or the deck of a yacht, but crossing a New York street. And instead of a bikini or cycling shorts and a crop top, she’s wearing a pair of tailored beige trousers, cinched with a black leather belt, pleated and full in the hip, loose of leg, teamed with a white T and an oversized shirt. It’s one part Diane Keaton in Annie Hall, one part Katharine Hepburn in The Philadelphia Story, one part Kennedy weekending at Martha’s Vineyard. Two weeks later, Danielle Haim wore an identical pair of pale, full, elegantly tailored trousers on the red carpet at the Brits, just a few days after model and entrepreneur Rosie Huntington-Whiteley posed on her Instagram in the same. (Fashion sleuths point to the Igor Pant by The Row, for sale at a cool £860, as being the originator of this trend.) In the last week of May, Jennifer Lawrence was photographed in New York wearing creamy front-pleat trousers with a cropped white T-shirt on the same day that the Duchess of Cambridge, more usually a dress-wearer, wore a slightly darker pair to attend the opening of a new hospital in Kirkwall, Scotland. International travel might be virtually grounded, but there is no stopping the global spread of this look. The first new look since we started to emerge from lockdown has landed, and it is not what anyone predicted. In what the fashion industry assumed was a two-horse race – either another term in office for the sweatpants we have grown comfortable with, or all-change to sequins and a roaring 20s revival – there has been an upset. Summer 2021 belongs to dad pants. If it was up to me, they’d be called Annie Hall Trousers, but the internet has embraced dad pants to the extent that it is now a search term on Zara, so the game is up. And the name does capture something about the mood of this look. Dad pants are sensible, reliable, a little bit nostalgic. Despite their illustrious fashion pedigree – the line of succession connects Hepburn and Keaton with an Armani-clad Richard Gere in American Gigolo – dad pants are egalitarian and a little bit goofy. Their trusty sidekick is an anonymous two-inch-wide leather belt – not the fancy double-G Gucci kind, but the kind you can pick up on the menswear floor of any department store in the world. The dad pant is where the desire for comfort, baked into our wardrobes over the past year, meets a desire for real life. Making your bottom half the focus of your outfit is the clearest of signals that you are dressing for real life rather than Zoom, while a loose pair of trousers is near enough to trackpants territory not to push anyone outside their lockdown comfort-dressing zone. Add to that the fact that they are gender neutral, can easily be sourced secondhand, and look great with a crop top if abs are your thing, and you have the perfect fashion formula for 2021. In Evelyn Waugh’s Vile Bodies, published in 1930, Agatha Runcible is turned away from a country hotel on account of wearing trousers. (“They made Miss Runcible stay outside, and brought her cold lamb and pickles in the car.”) In 1951, Katharine Hepburn used the staff entrance during her stay at Claridge’s because the London hotel did not permit women to wear “slacks” in the lobby. It is a backstory that brings, still, a certain swagger to a woman in a pair of grandly tailored trousers. “There’s an assertiveness to it,” says Jo Sykes, the creative director of Jigsaw, who had an image of 90s Christy Turlington in loose cream trousers and a white vest on her moodboard while designing her latest collection. (Jigsaw is backing high-waist, double-pleated trousers for autumn.) Sykes learned the art of perfect trousers working in the design studio of Giorgio Armani. “Getting the fit right is all about the crotch,” she says. “The rise at the front has to be the perfect length, and the back of the leg needs to fall from the fullest part of your bum rather than slumping underneath it.” She has perfected a waistband that is crisply buttoned at the front, but elasticated at the back. “The super-tailored waist is great if you’ve got Hailey Baldwin’s abs, but the core Jigsaw customer is 45-60 and she wants to be comfortable,” she says. A current Jigsaw bestseller is a pale herringbone Irish linen suit that has a three-buttoned loose blazer and fluid trousers. “I think right now people want to look tailored and presented, but the overall silhouette is looser.” David Fraser is the senior designer at Aligne, a new brand aiming to deliver sustainable fashion at an accessible price by partnering with factories that work with environmentally low-impact fabrics across all the brands they produce, in order to bring prices down. “The look is about scratching that itch to feel a bit more put together, a bit more in control,” he says of the burgeoning appetite for Aligne’s tailored trousers. “We’ve all felt quite out of control for a year, and we want to change that, but at the same time we want something quite soft and easy. This isn’t about rigid, boxy tailoring.” What’s more, a summer that many of us will spend in our home towns and cities rather than on a sun lounger calls for a different kind of warm-weather dressing, not the usual flimsy holiday wardrobe. “It’s nice to wear something that’s airy but not too revealing,” adds Fraser. At Joseph, another British label with a bluechip trouser pedigree, joint creative directors Anna Lundback Dyhr and Frederik Dyhr believe that a great pair of trousers should have “a sense of drama”. They are backing “elongated and elevated” fluid trousers, with high waistbands and deep pleats, for their two forthcoming collections. You don’t have to buy new to get this look. Daisy Marlow and Laura Johnson are the co-founders of Make Nu, a new kind of chic fashion business, which brings taste and knowhow to repurposing and reviving your preloved clothes in order to help you fall in love with them again. “If you’ve got a baggy pair of trousers with allowance at the waistband we can turn them into pleats. We can add belt loops. We can taper the legs,” says Marlow. For a sustainable and affordable route, she suggests going to secondhand stores for a roomy pair of men’s trousers in a nice fabric and having them adapted. “I love this look – it makes me think of late 1970s Bianca Jagger,” says Johnson. “It’s timeless, and we’re all about longevity at Make Nu.” Onloan is a fashion rental service that works a little like an old-school library card. Pay a subscription, and you can have two or four items on loan at any time. You get newness and sustainability on a Zara budget. “We keep hearing from our customers that rental is a great way to try out a new silhouette,” say co-founders Tamsin Chislett and Natalie Hasseck. “Right now we’ve got two incredible pairs of dad-silhouette trousers that are tenfold our most successful trousers of the moment. It’s taken us completely by surprise, because they are by a brilliant but under-the-radar Italian label, Jejia – no one knows the name, so it’s the shape that people are going for. They are perfectly cut at the waist, so that you can tuck in a white T and it sits perfectly.” In her 2011 memoir, Then Again, Diane Keaton writes that Woody Allen told her to “wear what you want to wear … move around like a real person” when he directed her in Annie Hall. What she wanted to wear was “what the cool-looking women on the streets of SoHo were wearing … Annie’s khaki pants, vest and tie came from them.” Ralph Lauren provided most of the clothes, but the styling concept came from Keaton’s fascination with downtown urban style. In 2021, after a year of dressing for the sofa or the park bench, the impulse to dress up for the city streets – to look cool – is back. And so are Annie Hall’s trousers.