It’s 1 March 1994, and at New York’s Radio City Music Hall, the 36th annual Grammy awards are under way. Though Cypress Hill’s Insane in the Membrane and Dr Dre & Snoop Dogg’s Nuthin’ But a “G” Thang are favourites for best rap performance by a duo or group, it’s Rebirth of Slick (Cool Like Dat), the debut single from Brooklyn-based underdogs Digable Planets, that wins.

And the upsets don’t stop there: collecting the award with bandmates Craig “Doodlebug” Irving and Mariana “Ladybug Mecca” Vieira, founder Ishmael “Butterfly” Butler gazes out at the celeb-packed room and kills the mood dead. “We’d like everybody to think about the people right outside this door that’s homeless,” he says. “As you sit in these $900 seats … they out there not eating at all. Also, we’d like to say to the universal Black family that one day we’re gonna recognise our true enemy. We’re gonna stop attacking each other, and maybe then we’ll get some changes going on.”

It was a defining show of seriousness from a trio misperceived as giddy, jazz-loving bohos. Before the year was done, Digable Planets released Blowout Comb, the substantive, subversive second album Irving describes as “about the pain and joy of being Black in America”. Now seen as a masterpiece of alternative hip-hop, the group are celebrating its 30th anniversary with a gig at EFG London jazz festival this week.

But only months after Blowout Comb’s release, the group imploded, the album having fallen on deaf ears. Irving reckons Butler’s speech that night might’ve had something to do with that. “I bet people thought, ‘Fuck these motherfuckers’,” he says today, on a video call from his home in Fresno, California. “But I don’t care who we pissed off. Because it was the truth. It was real.”

The speech was in character for Butler. Raised by civil rights activists, his parents’ beliefs weren’t just an influence but “the sediment of my being”, he says from his studio in Seattle, surrounded by instruments and gear. The son of a Black Panther, Irving was coming from a similar place. The pair met in Philadelphia in the late 80s, bonding over hip-hop aspirations and their grandmas living a block apart. Butler had already recorded demos with his group Digable Planets, though his bandmates had since quit. Irving quickly jumped aboard, and introduced Butler to a friend from Maryland.

The daughter of two Brazilian musicians, Mariana Vieira felt emboldened by hip-hop. “Black American music – hip-hop specifically – co-signed experiences I was having in America as an Afro-Latina girl,” she says, at home in Los Angeles. “It was everything to me – I needed it to survive. I’d begun writing down my own observations on the world. When hip-hop came into my life, I realised: ‘I can turn these words into rhymes now’.”

In Irving and Butler, Vieira found friends whose obsession with hip-hop ran as deep as hers. “We’d obsess over every word, every groove, every detail,” she remembers. “Entering these artists’ worlds was intoxicating.” Invited to rap with the boys, her audition rhymes became Nickel Bags off their 1993 debut album, Reachin’ (A New Refutation of Time and Space). “We were like, ‘Damn, she’s dope!’” remembers Butler. “Her delivery, her tone … She was something. The universe was looking out for us.”

Vieira was quickly familiarised with Butler’s “insect theory”, an ethos Butler says was inspired by “Funkadelic and Parliament records, my parents’ philosophies and reading lots of Marx and Jorge Luis Borges. The insect thing was: It’s not just about you, it’s about everybody. We’ll work on behalf of our culture, to make progress.”

“It was an egalitarian, communal vision,” Vieira says, “like the poor communities where I was raised, where we all looked out for each other.”

Their wider doctrine, meanwhile, was shaped by jazz. “My pop was a jazz head,” says Butler. “Jazz spoke to me, culturally and aesthetically: the mood, the pride, the discipline, the consciousness, the coolness. We weren’t just paying tribute – we were participating.” Vieira remembers afternoons studying album sleeves with Butler, “committing all the musicians’ names to memory. We adored this Black American art form born out of oppression and lack, but also remembrance of and deference to African culture. It felt like home, like a miracle.” They sampled jazz records, namechecked jazz artists and, later, performed alongside live jazz musicians.

Butler had been making industry contacts while interning at Sleeping Bag Records. “Ish gave a demo to Dennis Wheeler, this hippy A&R guy at Pendulum Records, who got us,” remembers Irving. Pendulum released their debut 12”, Rebirth of Slick, in November 1992, its killer Art Blakey sample accompanied by an artful black & white video that located the group on stage at a classy jazz club. Reachin’ followed the next February, opening on a Herbie Hancock sample, portraying Digable Planets as “weird motherfuckers … from the colourful ghettoes of outer space” and featuring copious shoutouts to forebears like Coltrane and Mingus. Their aesthetic had arrived fully formed.

But for all this playfulness, the album was grounded, too – the abortion-themed La Femme Fetal warned that the oft-threatened repeal of Roe v Wade would result in the deaths of young women, and recommended that listeners “fight against the fascists”. It feels painfully timely three decades on. “I didn’t think of it as a sociopolitical move at the time,” Butler says. “I thought, ‘this is how I feel, and I believe I’m right’. I knew from my mom, a social worker who’d helped young women in dire positions.”

“Le Femme Fetal’s always been timely,” adds Vieira, “because ever since Roe got passed, there’s always been a rightwing agenda to overturn it.” She pauses. “And they finally did it.”

Digable Planets’ arc was intense, but brief. Reachin’ peaked at No 5 in the Billboard R&B/Hip-Hop chart; shortly after the Grammys, work began on the follow-up. “I was ready to step it up,” remembers Butler, who got their live band to record interstitial pieces for “an updated Blaxploitation feel” and sampled these sessions to make new beats. Pink Floyd’s Dark Side of the Moon was a perhaps-unexpected influence. “Not the music,” he clarifies, “but its fluidity. I wanted to make an odyssey of a record.”

It wasn’t just the music that was bolder this time; the lyrics were more politically explicit, their themes of pride and pain coming brilliantly to the surface. “We wanted to let people know we still from the hood, that we never forgot about our people,” says Irving. But Pendulum blanched at the new album’s fierceness, its darkness. “They wanted another Rebirth of Slick,” says Irving. “When they heard how belligerent it was, how funky, they felt they couldn’t market it to the mainstream, ie white people. They felt it might offend them, make them uncomfortable.”

“They wanted us to stick with that whole ‘Black hippy’, ‘all-inclusive joyride’ vibe,” adds Butler. “But we had beliefs, thoughts and ideas. We wanted to go deeper into where we were actually coming from.”

Pendulum ultimately relented, releasing Blowout Comb in October 1994, but, says Vieira, “they didn’t have faith in it, and didn’t put much money towards promoting it”. As it failed to replicate the debut’s success, already-simmering tensions boiled over. “When you winning, everybody’s happy,” says Butler. “When you losing, whatever people ain’t happy about comes to the surface.”

“Everyone had their own camps, whispering in their ear,” nods Irving. “Ego got in the way of what we were trying to do.” Vieira’s mother died, then her father fell terminally ill. The centre could not hold. After a March 1995 appearance on Soul Train, Digable Planets split. “We needed a breather,” Vieira says. “We were so young.”

Years passed. Vieira recorded a solo album, shelved after the label folded; Irving relocated to Washington DC to develop other artists; Butler returned to his native Seattle, reinventing the hip-hop paradigm with his experimental Shabazz Palaces project, whose slew of albums and related releases – in particular, 2014’s ambient-rap curveball Lese Majesty – have enjoyed widespread acclaim, and earned Butler an A&R role with Sub Pop Records. But the pull of Digable Planets remained. In 2005, Vieira reached out and suggested they get back together, and a reunion tour of Europe was revelatory. “Lines around the block,” grins Irving, whistling.

They’ve toured irregularly ever since, and there have even been whispers of new music, though that has yet to materialise. There’s a sticking point, but if they know what it is, they aren’t saying. “I hope someday we can get it together,” says Vieira. “It would be a dream for me,” adds Butler. “I got hopes. I done had hopes for it for the longest while. But … hopefully.”

For now, these reunion tours are giving them life. “We realise what a gift this music has given us, what a blessing this is,” Vieira says. “On stage, I feel a freedom I don’t feel anywhere else.”

“This music has lasted in a way we couldn’t have imagined,” adds Butler. “As long as people ask us to perform it, we’ll answer. It’s the realisation of my wildest dream.”