Gen Z, the flats-only generation, has finally succumbed to the heel – albeit a tiny one. Long vocally anti-heel, the cohort who were born between 1997 and 2012 have famously shunned millennials’ obsession with Jimmy Choos in favour of pancake-flat shoes, from the Adidas Samba “It-trainer” to the split-toe Margiela Tabi and so-called “French girl ballet flats”.

But they now appear to be embracing a potential gateway heel, typically measuring in the region of 1.5in (3.8cm) or the height of a triple-A battery.

The kitten heel flip-flop has been seen on the feet of trendsetters Hailey Bieber and the model Kaia Gerber, and has featured in countless TikTok “fit-checks”; a street-style favourite, the shoe has become a way to channel the slinky style of the 90s this summer.

It’s also been the heel of choice for spectators in the Wimbledon crowd, as well as for contestants in the Love Island villa. The Emily in Paris star Lily Collins styled her black Manolo Blahnik pair with a white bandeau and capris to watch the men’s final last week, while several of the ITV show’s islanders have sported them while pulling potential love interests for chats by the fire pit.

On the high street, John Lewis says sales of kitten heel toe-post shoes, which feature a strap between the big toe and its neighbour, shot up 300% compared with last year, adding that the £109 thong sandals from its collection with Rejina Pyo “sold out very quickly”.

Luxury fashion labels including Chloé, Bottega Veneta and Max Mara have sent them down the catwalk, while searches for kitten heel flip-flops on resale app Depop have jumped 260% since April; at Vinted they are up 209% year on year. Meanwhile, fashion search platform Lyst reports a similar 202% surge in demand quarter on quarter.

So why is a revamp of the humble flip-flop persuading gen Z to finally step into heels?

Natalie Munro, a news writer at digital fashion publication Who What Wear, says the appeal lies in the fact that it’s a heel that doesn’t necessarily feel like one: “It’s still got that casual energy … so it’s not a very intimidating heel to wear.”

Part of that is, of course, its diminutive height. In-demand versions from brands like Toteme, Miu Miu, Zara and Vivaia measure between 1.5 and 2.1in, offering minimal lifts – perfect starter heels for a generation more used to “touching grass” than wearing stilettos.

Kitten heel flip-flops can endure the mileage of a morning commute, while not looking out of place on nights out. “In a lot of instances, it’s an appropriate shoe to wear to work and then into the evening as well,” says Munro, adding: “It’s obviously very heatwave appropriate.”

Sky-high heels were far more commonplace in the noughties. “Millennials were always out in heels,” says Munro. “For the office, for the club – they were such a go-to shoe.” For gen Z, however, whose coming of age coincided with the rise of comfort-first dressing in the pandemic, “flats have been the starting base for a lot of [their] relationship with shoe trends”.

Caroline Young, author of fashion and pop culture books including Style Tribes: The Fashion of Subcultures, thinks young people have a different understanding of heel height and femininity. “Kitten heels sit comfortably between heels and flats, and while they were once dismissed as a little dated and [not] conveying the sexual power of a stiletto”, the focus now is on being able to “move easily”, she says. “For gen Z, comfort has always been [more] important.”

According to Rebecca Shawcross, senior shoe curator at Northampton Museum and Art Gallery, and author of Shoes: An Illustrated History, “stilettos have for many years been worn as a power shoe, but I think the power these days rests with those women who chose comfort over discomfort and activity over an inability to run”.

It’s also a reaction to an era that has championed the kind of shoes you can scale mountains in: “Orthopaedic, gorpcore-coded shoes have dominated since the pandemic,” says British Vogue shopping editor Joy Montgomery, adding that now: “I think there’s a renewed craving for glamour in our wardrobes.”

Munro says the trend riffs off the more general flip-flop revival. The big rubber sandal rebrand can be credited to American luxury fashion label The Row, which triggered outrage when it unveiled its unremarkable rubber-soled $750 iteration.

The question now is whether the kitten heel flip-flop could become a gateway to higher heels for gen Z. Shawcross points out that kitten heels, which were popular in the 1780-90s, have been a transitional heel in the past. “They were known as Italian heels,” she says, “and marked the transition from women’s buckle latchet shoes that had reasonably high heels to the flat-soled shoes that characterised women’s shoes of the early 1800s.”

Munro thinks the shift is now possible, with wedges already making a comeback. It could, she says, “be an indication that we’re starting to move back into a high heel era again”.