In the late 1970s, Mike Stone changed punk for ever from the boot of a BMW. He had started Clay Records from a tiny record shop in Stoke-on-Trent, and after initially distributing the releases from the back of his car, Clay’s hardcore punk bands Discharge and GBH made the UK charts and are now considered pivotal influences on numerous metal styles from thrash metal to black metal, grindcore to an entire genre named after Discharge, D-beat.

Both bands have been covered by some of thrash metal’s biggest artists – Anthrax, Slayer, Sepultura and Metallica, whose frontman James Hetfield credits the British bands as “the beginning for me … I loved Discharge and GBH and still do.”

Discharge founder Terry “Tezz” Roberts was a schoolboy in Stoke when the band started in 1977 with his brother Tony (“Bones”, guitar) and bassist Roy “Rainy” Wainwright, following instructions in Sniffin’ Glue fanzine: “Here are three chords. Now start a band.” Forty-five miles away in Birmingham, GBH singer Colin Abrahall – still spiky-haired at 58 – saw the Ramones play at Birmingham’s Top Rank and decided: “The day I leave school I’m going to become a punk.”

The Birmingham scene was centred around the currently disused Crown pub near New Street station, which had once hosted the first Black Sabbath gig but by the late 70s was a punk-rock hotbed where GBH played (initially as Charged GBH), rehearsed, and even built the stage. “Everyone in there seemed to be in a band,” says Abrahall, when we meet pre-coronavirus crisis in their Digbeth rehearsal room, surrounded by posters from 40 years of his band. Birmingham was erupting with chart-bound pop – Duran Duran, UB40 and Dexys Midnight Runners – but the punk scene was DIY.

“I bought a bass guitar off a kid at school for £18,” says the singer. “Our first drum kit was an electric fire.” Hair was spiked up with everything from “Vaseline to egg whites, which made your head stink, so I discovered soap. That was great unless it rained, in which case we’d run around with Tesco bags on our heads.”

Unbeknown to either band, the man who would bring their music to the world was undergoing his own awakening in London. Mike Stone, pushing 30, wasn’t exactly a punk rocker. The former mobile DJ was working for the fledgling Beggars Banquet label when chancing on the Lurkers (who he’d subsequently manage, then sign to Clay) playing in a basement made him want to get involved. “They had the same energy and excitement as the Who,” he says over a coffee in Stoke. “I’d watched the Who open-mouthed live in Leeds when I was 15. But music had become stagnant – punk was what was missing.”

Stone relocated to Stoke after meeting and marrying a woman who lived there. He started a shop, Mike Stone’s Records, and a label called Clay Records at 26 Hope Street, funding the latter with £1,000 from a relative and naming it after the city’s potteries. Today, the site – now a disused fast-food joint awaiting demolition – looks lonely and unloved. Back then it was a dynamo of musical revolution, the wheels of which were initially set in motion by a 17-year-old girl.

Tanya Rich on the day she met Discharge. Photograph: Publicity image

Privately educated Tanya Rich, an unlikely rebel, had cut her hair and dyed it “all sorts of colours” after hearing the Saints song (I’m) Stranded. Punks in Stoke were rare enough; female ones nonexistent. “Akko, the original Discharge drummer Anthony Axon, saw me and ran down the road to tell the boys, ‘There’s a female punk in Stoke!’” she says with a laugh, still blue-haired at 59. “They ran back and said, ‘We’re a band’.”

Rich dated Rainy, then became Discharge’s manager, driving their success. “Punk had all these female artists, from Siouxsie Sioux to Beki Bondage,” she explains. “Female managers were unknown. But I had chutzpah. I got them gigs with the Clash, the Ruts and the Damned.” Rich gave Stone a demo tape containing songs such as Acne. He remembers saying: “You sound like the Sex Pistols – what’s the point? But then they came back with something else.”

As Tezz tells it, the classic Discharge sound resulted when roadie Kelvin “Cal” Morris replaced him as vocalist, bringing growling, shouty vocals of the kind that are now standard in extreme metal. “I switched to drums and did the [furiously fast] D-beat,” Tezz says. “The band changed overnight.” Stone saw the revamped band play live – a slab of raw meat hurled his way almost hit him. “I think they were trying to impress me,” he says. “But suddenly, Discharge sounded like a bulldozer. They made the Pistols sound like Take That.” When Stone saw GBH supporting Discharge at the Victoria Hall in Hanley he thought: “I’ll sign them as well.”

GBH singer Abrahall’s theory about why punk’s second wave was much harder and faster is that “the audience had become the bands, but we didn’t have the same musical skills [as the Clash et al], so we went 100mph”. Tezz suggests that the growing metal element was because: “we all loved Motörhead, although punks wouldn’t admit it”.

The intense music also mirrored its environment. “People would either take photographs of us or want to fight us,” Rich says, while Abrahall remembers “being chased by bikers, skinheads, or straights – as we called normal people. Police vans would wait outside the Crown targeting punk rockers.”

“The gigs were like wars,” says Discharge’s Tezz. “Violence every night. People would think, ‘What’s this noise?’ and throw shit at us. When we opened for the UK Subs it turned into a massive battle.” A wry laugh. “When we started getting popular it thinned out the criminals.”

Abrahall wrote GBH’s first song, Generals, on hearing that the government were considering bringing back conscription. Discharge meanwhile sang about “being shit on far too long” (Decontrol) or the evil of warfare (Never Again). “Cal was into Crass and always had his head in pamphlets,” Tezz explains. “That’s where he got ideas from.” They showed the nuclear survival film series Protect and Survive at gigs, while scene character Biffo the Gasmask would “dress up as a housemaid in a gas mask, vacuuming the stage”.

Mike Stone, who ran Clay Records in Hanley, Stoke-on-Trent, outside his former shop in the city centre. Photograph: Christopher Thomond/the Guardian

Stone captured this creative explosion as label head and producer, despite knowing little about studios. “But I’d watched Steve Lillywhite working with [mod band] the Merton Parkas,” he explains. “In my naivety, I recorded Cal singing twice and layered one vocal over another. It sounded like a wall of sound. So I did the same with the guitars.”

For Discharge’s Realities of War EP, in 1980, Stone went to take a band shot at the back of 26 Hope Street. “But Cal didn’t want his photo taken, so turned his back”. The resulting closeup of Morris’s studded leather jacket became “the most iconic sleeve I ever released”. Stone drove a bootful of the EP to “smirking distributors, who’d go, ‘OK, I’ll take a few.’ But then after John Peel played it on Radio 1 it was like a hurricane. Punks all over the country wanted the record, and thousands of them copied that leather jacket.”

Clay’s roster weren’t the only British hardcore punk bands. Other labels sprang up, notably No Future. In 1981, Edinburgh band The Exploited – who formed two years after Discharge – appeared on Top of the Pops. After the show, guitarist Big John Duncan says, “women old enough to be our mums were coming up to us and being really nice, but the song Dead Cities captured a moment when cities were rioting”. The BBC producers also wanted Discharge, but Morris turned them down. “Real shame,” sighs Tezz, drily. “It would have been nice for my mum.”

Nevertheless, Discharge’s 1982 debut Hear Nothing, See Nothing, Say Nothing went Top 40, while GBH’s City Baby Attacked By Rats reached No 17 on the charts. “In between a Jimi Hendrix collection and Paul McCartney,” chuckles Stone. “I thought, fuck me, I’ve done it.” Both bands enjoyed more success before the collapse of distributor Pinnacle in the mid-80s took the label down. “I lost £25,000,” Stone says. “It wiped me out.”

GBH continue touring and recording, reaching a new audience after Slayer covered Sick Boy. Abrahall has spotted Travis Barker and Rita Ora wearing GBH T-shirts, and is grateful to Stone for “giving me a start, and a very happy life”. Gizz Butt, former guitarist of English Dogs who began their career on Clay as hardcore punks, remembers the 1984 article hailing them as “the dawning of speedcore”. Meanwhile, three-quarters of the classic-era Discharge lineup are together, and Metallica have been spotted at their gigs.

Forty years on, Tezz is keen to credit Stone for “taking a chance, when other labels said we made noise, not music”, although he struggles to comprehend the impact of a band he started after selling frozen fish to buy equipment. “I can’t listen to those bands and say, ‘That’s what we invented.’ But I know we changed the direction of music.”

The man who made it possible still manages old signings Demon and recently did courier work. Sadly, Stone sold the rights to his catalogue when he was broke years ago, but is proud of what his label started. As he drops me off at Stoke station, he nods towards the statue of renowned potter Josiah Wedgwood and jokes: “There should be one of me.”

• Discharge’s Protest and Survive – The Anthology is out on BMG. GBH are scheduled to play Rebellion punk festival in Blackpool, 6-9 August.

• This story was amended on 21 April 2020 to correct the origins of band The Exploited, who are from Edinburgh not Glasgow. An earlier version also wrongly described Sepultura as one of the “big four” thrash metal bands, widely acknowledged as Metallica, Slayer, Anthrax and Megadeth.