To paraphrase Sir Mix-A-Lot, rap’s prophetic connoisseur of “booty”, the internet likes big butts, and it cannot lie. We are living, it seems, through the radical age of celebrating curvy women, where the call for bigger bums, tinier waists and thicker thighs is having something of a moment. In body image terms, the waifish rail-thin aesthetic is out and the cartoonish proportions of Kim Kardashian West are (cinched) in.

“The demand is huge,” confirms Dr Gary Horn, of the Harley Buttock Clinic, an augmentation specialist. Surgery, fillers and implants on bottoms have accounted for one of the fastest-growing types of cosmetic surgery in the US for the past two years, according to the American Society of Plastic Surgeons.

Bums are, literally, a growth market. Each week at Horn’s central London practice 15 to 20 women inquire about procedures to transfer fat from their stomachs and have it pumped into their bottoms. Silicone implants and non-surgical hyaluronic acid injections are also more common. “Five years ago, everyone wanted liposuction to remove saddlebags, now [they] want volume on their hips and buttocks. It’s definitely a fashion and media thing – and it’s going up,” says Horn.

At an early-morning Quickie Butts class at London fitness studio Frame, instructor Eian Crockatt leads a roomful of women pumping through squats, lunges and hip extensions specifically designed to sculpt perkier, bigger bottoms.

Holly Keeble, who works in product development for a food and drinks company, tries to attend once a week. “I have quite a big bum for my size and it’s definitely more acceptable to have a bigger arse now,” she says after the 30-minute class, “and that curvy, toned look is something everyone is aspiring to at the moment.” Frame has declared May “BUTT month” and scheduled extra classes to meet the demand from its regulars.

Bodily proportions that have come naturally for many black, Latina and Asian women are now being mainstreamed and fetishised in popular culture by way of celebrity, fashion and social media. Ashley Graham, the first plus-sized British Vogue cover star, is now one of the highest-paid models in the world; Tess Holliday has made a career of championing body positivity. But while both have set the mood music, the current emphasis is on being “thicc” – a play on thick, and shorthand for a body shape that is slim of waist but big on thighs and sides. Thicc Thursday has become an internet meme; influencers such as Blindian Babygirl (96,400 followers) and Katya Elise Henry (4.9 million followers) have been born on Instagram simply for “flaunting” curves where bubble butts are the focal point.

On the high street, “bum-sculpting leggings” have been selling out at Sweaty Betty for up to £95 per pair and an industry of bum creams, scrubs and collagen masks – from Sol de Janeiro’s Brazilian bum bum cream to Anese’s That Booty Duo – has emerged, to be reviewed in earnest online as cult beauty buys.

Asos Curve range for ‘thicc’ women.

Kelechi Okafor, who runs pole-fitness classes from a chic studio in Peckham, south London, is cheerfully sceptical. “Women of colour aren’t being seen or accepted any differently by society because big bums and snatched waists are apparently trendy now. Our natural features are only worthwhile and celebrated on women who have had surgery to look that way – who then promote flat-tummy teas, waist trainers and appetite-suppressing lollies.”

Still, Okafor finds, it is now easier to buy clothes that accommodate diverse body shapes. Asos, the most popular online fashion retailer in the UK, has been selling a popular Curve range for so-called thicc women since 2010. River Island followed in 2015 and Marks & Spencer launched its own reinvented plus-size line, also called Curve, in January.

Skinny no longer suits, says personal trainer Nyambe Ikasaya. He demonstrates the intimidating array of deadlifts and weighted hip thrusts (where a barbell is placed across the abdomen) taken up by a hard core of women, “mostly between 25 and 35”, who then post the results online. “It can be dangerous if you don’t have the right technique. But the gluteus maximus is the biggest muscle in your body – building strength there and keeping it fired up and active is good for your core. So, overall, it’s not the unhealthiest fitness trend.”

And however one views the new dash for surgical enhancement of the behind, the thicc revolution at least means that one cliched expression of female body insecurity needs to be radically rethought. These days, the supportive answer to the question “Does my bum look big in this?” is “yes”.

Instagram favourites

Beyoncé (115m Instagram followers)

Owner of the most prized thighs in the business, Beyoncé has been open about how hard it is to look the way she does. “I am a natural fat person, just dying to get out,” she told Bang magazine in 2014. “I go through agonies to keep my stomach as flat as possible”

Nicki Minaj (86.7m followers)

The rapper styles herself as a human Barbie; her biggest hit - Anaconda - was a paean to the joys of her own bum.

Amber Rose (17.1m followers)

The model who once dated Kanye West has been as famous for her behind as she has for her cropped blond hair, and has launched her own SlutWalk marches to protest victim-shaming and rape culture.

Bria Myles (1.5m followers)

A dancer and ex-girlfriend to rapper Drake, Myles has grown a career as a digital influencer in part because of her physical assets.