This is not your standard punk-rock gig, even if the scruffy venue used to be a warehouse and guitars are being liberally thrashed. That’s mainly because the 150-strong crowd is not uniformly white – more than half are people of colour. Then there’s the figure crooning with restrained menace on stage. She goes by the name Ms Mohammed, specialises in “rock’n’dhol” (referencing a type of Indian drum) and says she’s part of a resurgence in British POC guitar bands. “It feels like a burgeoning scene, and it’s about time really,” she says.

Ms Mohammed was a headliner at last weekend’s Decolonise Fest, a three-day event in south London featuring only bands of colour. In the festival’s second year, organisers received more than 100 applications to play – proof, they say, that the talent is out there, despite few POC being prominent in UK guitar music (they also run regular POC nights under the name DIY Diaspora Punx). In the US, bands such as Vagabon and Mitski have been breaking American indie’s white mould. Why hasn’t the same happened in multicultural Britain?

Facebook Twitter Pinterest X-Ray Spex in 1978. From left: Paul Dean, BP Hurding, Jak Airport, Rudi Thompson and Poly Styrene. Photograph: Evening Standard/Getty

British guitar music wasn’t always so white. People of colour were vital in founding the UK’s punk and indie scenes. But while everyone knows the Sex Pistols and the Smiths, Poly Styrene from X-Ray Spex is hardly a household name, while the contribution of Zeke Manyika to Orange Juice is often overlooked. Decolonise was set up in part to confront this “whitewashing”, says organiser Jon Bellebono. “Bands with people of colour have always existed and lots of them have been successful.” Their legacy, Bellebono argues, is just not celebrated in the same way.

In Britpop, regarded by many as the last golden era of British guitar music, bands led by POC such as Cornershop and Echobelly again tend to be left on the story’s fringes. Both were popular at the time, although their members’ heritage frequently influenced how they were perceived. Echobelly’s Sonya Madan feels too much attention was given to her background – Melody Maker once described her as a “tiny, kickboxing Indian”. But, ultimately, she considers the era’s exploration of British identity as a positive one: “The scene was pretty inclusive,” she says. “Britpop was many things, but it was not a racist movement.”

Perhaps Britpop is more to blame for what it left behind. Apart from helping to revive fantasies of Britain’s cultural greatness, guitar music grew less diverse in its wake. By the late 90s, indie had become synonymous with whiteness, which endures: Bloc Party’s Kele Okereke, a rare exception among predominantly white guitar bands, has described the British scene as “one of the few arenas where diversity is not encouraged”.

Facebook Twitter Pinterest Edwyn Collins and Zeke Manyika of Orange Juice. Photograph: Mike Prior/Redferns

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London’s self-proclaimed “three-tone” punk trio the Tuts are getting mainstream attention: they’ve sold out small clubs on nationwide tours and played Glastonbury. And yet they remain unsigned. Drummer Beverley Ishmael thinks that with guitar music less popular than it used to be, labels don’t want to gamble on POC. “They’re going to go with the safe option, which is white-man bands,” she says. This is why events such as Decolonise are so important, Ishmael adds, inspiring young POC to get up on stage themselves: “If you see someone who represents you, who looks like you, has hair like you, you’re gonna be like, ‘Oh yeah, I can do that, too’.”

The Tuts’ singer and guitarist Nadia Javed, who appeared on a panel at this year’s Decolonise festival, has no illusions about the hurdles faced by POC indie bands. “I feel like white cis men get away with being mediocre,” she says. “When people see women, and then women of colour as well, they expect twice the amount of work.” And even when there is recognition, bands of colour often find themselves on otherwise all-white lineups. “Everyone is trying desperately to get that one slot that’s available to them,” says Javed. “There have been times where I’ve legitimately doubted myself: have I got this really good gig because of my music, or am I ticking a diversity quota?” says experimental industrial-rock artist Kapil Seshasayee, another Decolonise headliner. As well as making an album about oppression in the Indian caste system, Seshasayee is a DIY promoter in Glasgow. “A lot of the time with diversity, I have to force it to happen,” he says.

The Tuts have found themselves put on a festival’s “urban” stage alongside MCs and grime artists, while critics describe Big Joanie, an emerging black feminist punk band, as “soulful”. “We’re closer to Nirvana than a soul band,” says singer-guitarist Stephanie Phillips. “The whole idea that you see black women and they should be there warbling out some Beyoncé to you – it’s [about] not being able to critique what’s in front of you because of your own ingrained prejudice.” It was Phillips who thought up Decolonise, having felt a “vacuum” existed since her teenage years in Wolverhampton, “and remembering there was literally nothing, no kind of acceptance for people like me”.

Bands such as Nova Twins, Skinny Girl Diet and Sacred Paws are attracting attention, although Phillips is cautious: “It’s a long-term thing, it’s not going to change overnight.” But Ms Mohammed wonders if a flagging scene can afford to continue overlooking POC bands. She has a message for the industry: “We are the future, so stop fucking ignoring us.”