At just before 9am on a bright April morning in Greenwich, south-east London, runners gather in the shadow of the Cutty Sark. There are just a few at first, then more and more until the group numbers around 40. It’s a little awkward (for a first-timer like me, at least) as we shiver and make small talk. But soon we coalesce to form a big circle and run through a warm-up before doing a gentle 5km around Blackheath – we’ll be installed in a local cafe by 10am.

A version of this scene can be found up and down the country every weekend. Running seems to be more popular than ever – almost 580,000 people applied for this weekend’s London Marathon, an increase of 120,000 on the year before – but recently there has been a boom in casual, community-focused running clubs that organise regular turn-up-and-run events for people looking to supplement their training, meet new friends, or simply get out of the house.

I joined up with the charmingly named Runner Beans Club (RBC) – named for the founders’ desire to end their run with a coffee – but I could just as easily have met with Run Happy in Sheffield, Glasgow’s Croissant Run Club, Freelancers Running Club in Leeds or the Left Handed Giant Run Club in Bristol.

“It’s really hard to find community in London,” says Lydia Douglas, 28, co-founder of RBC, who only started running seriously in lockdown, and likes that it’s a way for people to meet and hang out that doesn’t involve alcohol. Douglas and her partner Joel Sanders established RBC 18 months ago, joining the likes of Your Friendly Runners (Hackney), Mafia Moves (Tottenham) and Scrambled Legs (Battersea) in the capital.

This relaxed, convivial alternative to traditional running clubs, which are focused on formal training and competition, has been around for a while, says Ben Hobson, multi-platform director at Runner’s World UK, who traces it back to London’s Run Dem Crew, which was founded in 2007. “The running was part of it but it was more about bringing people together,” he says. But the concept has boomed since the pandemic – expect positive vibes, group photos, and a shared love of cafe culture.

At RBC, a photographer runs with the group. “A lot of people have got into running via social media,” says Hobson, who notes how the uptick in casual running clubs can be linked to the sport’s aesthetic, and how it fits into a wider trend for technical adventurewear. “They see the similarities with what they want to wear on a day-to-day casual basis,” he says, listing cool outdoor brands such as Arc’teryx, Hoka and Satisfy, which all make stylish, up-market running kit. (A pair of Satisfy’s eight-inch Techsilk shorts cost an eye-watering £180.)

In Greenwich, there is definitely a look. For starters, everyone is young, ranging from early-twenties to late-thirties. And there are lots of tight, cycling-style shorts, brightly coloured trainers with enormous foam soles, visor-like sunglasses and even the odd ultramarathon-style backpack.

The common thread, though, is merchandise. Most of the runners are wearing either the white RBC club tee or the green club socks, or both. The shirt is just a simple crew neck with the club logo – a coffee cup with legs – printed small on the front, and large on the back. Definitely more streetwear than marathon-wear.

Merch has become an integral part of the casual running club scene, with every club offering something, ranging from baseball caps to technical running jackets. Douglas and Sanders didn’t establish RBC with merch in mind, but a clear demand soon materialised. “You’re inspired by the other clubs,” says Douglas, “and there were a lot of people asking for it.” One runner told me that it’s good for members to have something to “buy into” when they join, while another admitted that she didn’t have any RBC merch, but buys whatever Your Friendly Runners produces as soon as it drops.

Considering the nature of the core consumer base – young, creative, affluent, style-conscious and social media savvy – it’s perhaps unsurprising that the running club shirt has also become a marker of cool in day-to-day style. “When I wear this [RBC shirt], I feel like [there’s] something bigger, like I’m part of a tribe,” says Kyle Ayuba, 28, a designer and member of RBC, noting that he often wears it away from running. “I can wear it for sport, or for lifestyle,” he continues. “It feels very universal.”

RBC produces its merch via Everpress, an online retailer that allows individuals to upload designs and sell stock on a made-to-order basis. Gaia Di Siena, senior brand marketing manager at Everpress, says sport has long been a recurring theme, but describes a recent “phenomenon” of “run-themed” T-shirts, with many promoting completely fictitious clubs. “I’m not surprised as running is arguably the activity [that] anyone is getting into right now,” she says, noting how designs available on Everpress tend to “mirror what is currently relevant in culture and society”.

Hobson believes that fashion and running have always “coexisted”, pointing to the current ubiquity of New Balance’s 990 trainer, which was originally released in 1982 as a running shoe. But also that the sport’s recent rise in the style stakes has pushed prices up, making people feel that they need to spend lots of money to be involved. That said, anything that gets people running is good. “If it means more people feel like there’s a look for them, and they can go running and feel comfortable in an aesthetic they’re chasing, then go for it.”