Let’s talk about sex, shall we? Fashion and sex, that is. First things first: any conversation about sex needs to be an honest one, so let’s cut straight to the chase. Sex appeal will always be an integral part of fashion, even if sexy has become a less straightforward compliment after MeToo. So please, there’s no point pretending that we are too woke to care about looking hot these days. We still care. Nobody is taking vows of sartorial chastity here. But perhaps we are making some progress in how we think about sex and fashion if we are more conscious of whose rules are being played by, and whose needs are being met. As long as the survival of the human race depends on sex, looking attractive isn’t going out of fashion. But there is room for evolution.

It is Valentine’s weekend, and dressing for date night is the hot spot where the rules of attraction meet the rules of social convention. Which means that some Valentine looks might just be a little different this year, in the MeToo afterglow. The neckline might be altered, or the skirt might be a new length. Or maybe the clothes are the same but you might wear different underwear or decide against the high court shoes with toe cleavage, and look – and feel – different as a result. The way we dress for date night through the years reveals so much about our changing attitudes to sex. Braless under a silk blouse in the midst of the sexual emancipation of the early 70s. Spike-heeled and armoured in sequins in the competitively charged, battle-of-the-boardroom 80s. Unravelled and lipstick-smudged in the fog of 90s grunge when a Saturday night was more about getting high than getting laid.

A Gucci model at Paris fashion week … dressed in a way that might work for a portrait sitting with Leonardo da Vinci rather than Helmut Newton. Photograph: Victor VIRGILE/Gamma-Rapho via Getty Images

It is 18 months – three seasons, in fashion terms – since the MeToo movement was born. In that time, fashion’s centre of gravity has shifted away from sex. Hemlines are longer, silhouettes are looser. From London to Milan to Paris to New York, on glitzy spotlit runways polished to a mirror shine and on catwalks marked out with tape on concrete floors, a new course is being set. From Stella McCartney to Erdem, Coach to Loewe, Dior to Max Mara, there are skirts that swish the ankle and sleeves that graze the fingertips. Fashion has shifted the emphasis from skin to fabric. As a sweeping generalisation, there are more sweeping hemlines. Gucci, the runaway fashion success story of this decade, peoples its catwalks and advertising campaigns with women who would appear to be dressed in a way that might work for a portrait sitting with Leonardo da Vinci rather than for one with Helmut Newton.

Roland Mouret, a fashion icon for two decades, has recently gravitated away from the siren curves of his Galaxy dress, revisiting the pleats and cascades he learned while working with Yohji Yamamoto and Issey Miyake in his 20s. At his spring/summer 19 show, models wore badges in support of the MeToo movement and catwalked on the roof of the National Theatre to the sound of Aretha Franklin singing Natural Woman. Mouret said at the time that the new silhouette felt like a redefinition of his relationship with the female body. In the second half of her decade in fashion, Victoria Beckham, too, has pivoted firmly away from fitted dresses and toward loose, fluid separates. Such silhouettes – once the hallmark of alternative, arthouse fashion – have become mainstream. Vanessa Spence, design director at Asos, confirms the shift is happening on the high street. “The midi length has become a staple in our fashion vocabulary. Necklines still vary, but we have recently seen more of a focus on the back as an exposed area.” Sexy, she says, is no longer a concept that takes up more bandwidth in womenswear than men’s. “It’s the same across the sexes – which is surely a good thing.”

‘The emphasis has switched from skin to fabric’ … model Kaia Gerber at the Max Mara show during Milan fashion week spring/summer 2019. Photograph: Jacopo Raule/Getty Images

There will always be cross-pollination between sex and fashion, but MeToo has prompted a conversation about healthy boundaries around nudity and exposure. Changing facilities backstage at fashion shows are one issue being brought into the spotlight. It was long considered perfectly normal for an assortment of well-wishers, journalists, celebrities, friends of the designer – most, of course, with a camera phone in their pocket – to crowd immediately after a show into the open-plan backstage area where models were scrambling out of their show looks and into their own clothes. A year ago, New York fashion week was the first to address this, pledging “a safe and respectful working environment” with private changing areas. During London fashion week last September, the British model Edie Campbell spoke to Radio 4 about the ongoing lack of privacy at some London shows, describing it as “bizarre, uncomfortable and humiliating”. Awareness is growing that an expectation of endless female nudity is not a healthy baseline for any industry.

The meteoric impact of MeToo on what it means to dress up and look your best became clear a year ago, when the Golden Globes was the first red carpet to turn black. It was a gesture of female solidarity from Hollywood’s women, in an industry reeling in the Weinstein fallout. A black dress for black tie is hardly revolutionary, yet the dresses became the story of the night. The winners’ list is now a distant memory, but the red carpet blackout remains a landmark moment. The world was reminded of the power of an outfit – even one that stays within the guardrails of convention – to send a powerful message. Natalie Portman, Elisabeth Moss, Meryl Streep, Angelina Jolie, Penélope Cruz and Salma Hayek wore long black gowns with long sleeves. In each case, the dress had a decorative element that lightened the mood – a sheer layer, a split in the skirt or a portrait neckline. Many actresses left husbands and boyfriends at home to pair up with female activists for the night, which threw into sharp relief the traditional award show optics that see an actress nominated for an Oscar totter in a tiny, pastel-toned frock on the arm of a man in a suit, as if she were a magician’s assistant about to be put in a box and sawn in half.

At the 2017 Golden Globes women wore black as a gesture of solidarity and in support of anti-harrassment campaigns. Photograph: Chris Pizzello/Invision/AP

But if the first half of 2018 belonged to a swelling tide of demure black-tie dressing, the second half was dominated by an angry backlash against catwalk near-nudity. The exit of Phoebe Philo from Céline after 10 years had been felt as a body blow by women who had held dear her philosophy that catwalk fashion could be an elevated woman-friendly wardrobe rather than date-bait. It was with unfortunate timing that her successor, Hedi Slimane, unveiled a debut dominated by doll-sized party dresses – one that seemed the polar opposite of what the house had stood for under Philo – on the very day of the Brett Kavanaugh sexual misconduct hearings in Washington last September. Emotions were running high, and Slimane’s dolly-drop aesthetic became a lightning rod for female fury.

Male designers mansplaining female sexuality to the women who buy their clothes is not new. But the context has changed, and in fashion, context is all. Engagement with the world is what makes fashion more than simply clothes. It is, quite literally, what makes it fashion. Two months after Slimane’s show, the Victoria’s Secret models came bounding down their runway, with the tried-and-tested formula of bouncy breasts and jutting hipbones, angel wings and skimpy boudoir lace knickers which made this the most popular fashion show in the world just a few years ago. This time the spectacle was met with critical scorn (website Vox ran a feature with the headline The Stubborn Irrelevance Of The Victoria’s Secret Fashion Show), falling ratings and – most tellingly – declining sales.

A model at the Christopher Kane show, London fashion week, 2018 – the collection was adorned with drawings and quotes from the 70s manual The Joy Of Sex. Photograph: Victor VIRGILE/Gamma-Rapho via Getty Images

London fashion week has never been afraid of controversy. While other cities have reacted to the new climate by shying away from the idea of sex altogether, designers Christopher Kane and Michael Halpern are among those tackling the new rules of sexy dressing head-on, and reaching for a new body-positive, female-first way to talk about sex on the catwalk.

A frank curiosity about sex has always been part of Kane’s aesthetic – his spring 2014 season featured sweaters embroidered with illustrations of the reproductive organs of flowers – and in February last year, he waded into the MeToo debate with a collection adorned with drawings and quotes from the seminal 70s manual The Joy Of Sex. Six months later, he was back with a spring 2019 collection soundtracked by a David Attenborough narration about sexual behaviour in animals and Marilyn Monroe talking about how society defined her as a sex object and then despised her because of it. “There are no taboos in my studio,” Kane said after that show. “To be bluntly honest,” he told Vogue at the time, “we wear clothes to attract members of the opposite sex and of our own sex. That’s what fashion is.” Meanwhile Halpern, who burst on to the fashion scene in 2017 with sequin dresses so minuscule they might have turned heads at Studio 54, says he relies “super heavily” on the opinions of his mum and sister, “who are both feminists – of course. My focus is on being aware and awake to what women want.”

Penny Martin was almost a decade ahead of this shift when she launched The Gentlewoman magazine back in 2010. “It was the zenith of the weeklies, when the newsstand was crammed with reality TV celebrities with barely any clothes and shouty coverlines,” she recalls. “Our mission was to be the opposite of that – to give both the cover stars and the readers back their dignity.” The Gentlewoman came to be aligned with a particular kind of woman-friendly fashion, epitomised by what Phoebe Philo was doing at Céline. “Women want clothes that give them pleasure, without undermining them,” Martin says. “And I wouldn’t be in this business if I didn’t think providing women with the tools they deserve to get respect in both their working and private lives wasn’t a worthwhile ambition.”

Although certain sections of the media would love to frame this debate as a catfight, there is little appetite in the fashion industry for slut-shaming of women who choose to wear tiny, revealing dresses. (To paraphrase Voltaire: I may not like what you wear, but I will defend to the death your right to wear it.) What we wear for date night is part and parcel of sexual politics, but surely there is room for making the point that a woman’s erotic impact is not all that she is, without policing anyone’s wardrobe. “My take on it, as editor of Elle,” says Anne-Marie Curtis, “is that a modern woman wants the freedom to look sexy when she wants to. But that fashion can’t be about having to wear a pencil skirt to get a promotion, or having to wear a low-cut dress to make your boyfriend happy.

Michael Halpern tackled the new rules of sexy head on in his London fashion week show. Photograph: WWD/REX/Shutterstock

Every single image that goes into Elle goes through our modern, feminist lens. If I am looking at a shoot and there’s a pose that I feel makes the model look vulnerable, I won’t run that picture. We just did an edit of a shoot and there were images that I took out, because I always want the woman to look like she is owning the image.”

But unlike a longer hemline, fashion’s stronger attitude cannot be measured in inches or plotted on a graph. “It comes down to intention,” Halpern says. “What makes my friends and the women in my family feel empowered is self-worth, self-definition. It’s about not letting someone else put you in a box.”

For generations, teenage girls’ teachers have used the does-it-touch-the-floor-when-you-kneel test to establish the minxiness of a skirt. But calibrations of sex appeal are more complex. A pose in which a model is lying on a sofa can project laid-back confidence or exposed vulnerability, and the overall effect depends not only on the clothes but on the lighting, the facial expression. The same minidress can be framed as a celebratory portrait of raw female power, or an exploitative image of a woman underdressed and undefended. The highly visually literate modern fashion consumer is attuned to such subtleties, which is precisely why the dog-whistle crassness of Victoria’s Secret feels so out of step with our times. “The readers of women’s magazines, and of fashion photographs, are so literate,” Martin says. “An infinitesimal degree of ‘wrong’ can be vast in this context, instantly breaking the spell.”

Sex as something unspoken, as a scent caught on the air, is part of fashion’s magic spell. When the zeitgeist is embracing a new era of informed consent, the sheer-black-stocking vibe of fashion’s traditional date-night mode can feel like an uncomfortable hangover from another era. A new dress may not change the world. But it could make date night a triumph. The rules are up to you.