It’s general election night in the Ebbw Vale mining institute and four Englishmen are telling the Welsh about Wales’s past. They wear ties, rather bravely, in front of pint-sinking choristers and local rockers in 1970s tour T-shirts. Above the stage, footage plays of mid-20th century miners, their eyes shining like anthracite, cigarettes dangling from their lips. “The arrogant strut of the lords of the coalface,” purrs Richard Burton through the speakers, “looking at the posh people with hostile eyes.” These miners look like rock stars, much more so than Public Service Broadcasting, who are operating the machinery tonight.

Between 2013 and 2015, Public Service Broadcasting ploughed a fertile furrow in the pop landscape with two albums sampling old public information films over guitar-slathered electronica: Boys’ Own adventures about space, Spitfires and the second world war. They return with a very different record: Every Valley. Chronicling the rise and fall of the Welsh coal industry, it was recorded in the Ebbw Vale institute, which stands in one the most deprived areas of a country predicted to swing closer to Tory tonight. Last year, people here voted heavily to leave the EU.

This record remembers when the idea of being working-class didn’t mean that you couldn’t appreciate art or poetry. J Willgoose Esq

Tonight’s gig was booked long before the election was called and frontman J. Willgoose Esq (bandmates JF Abraham and Wrigglesworth have similar, Molesworthian monikers) sits in an upstairs counselling room, without a bow tie for now, looking nervous. “We’re going to take an absolute pounding, I think.”

He’s talking about Labour. Every Valley is a project born of his renewed interest in politics and a society he feels is smothering opportunity and potential in ordinary people. “That horrible phrase ‘stay in your lane’… this record rails against that and remembers the desire for bettering yourself that came from communities that coalesced around a single industry, when there was more political engagement and the idea of being working-class didn’t mean that you couldn’t appreciate art or poetry.”

Public Service Broadcasting frontman J Willgoose Esq during the 8 June gig at the Ebbw Vale Institute. Photograph: Shaun Gordon

Willgoose first had the idea for Every Valley before 2015’s Race For Space, wanting to get away from “big, epic subjects… and do something on a more human level”. The album’s themes aren’t just about Wales, either, he adds – its title is deliberately universal.

Despite “vague connections” to the country thanks to a half-Welsh grandmother, Willgoose has been wary with this project about being a Londoner looking in. He recorded interviews with old miners through the NUM in Pontypridd and pored over mountains of audio and film at the South Wales Miners’ Library at Swansea University. “I expected to be viewed with suspicious half-glances, constantly,” he says. “But that hasn’t happened once. Everyone’s been supportive, welcoming and open… and making the same jokes about Brexit as we do in London.” There’s a story still here, you sense, that bears retelling.

Every Valley tells this story very inclusively. Women are the subject of the moving They Gave Me a Lamp (“If you could get the women into one meeting or get involved in one thing, you could see them as this other life,” says the voice of a local woman, Margaret Donovan). You + Me is a bilingual duet with Lisa Jên Brown from 9Bach, to address “the history of English people being absolutely awful in terms of the Welsh language,” Willgoose says. James Dean Bradfield turns poet Idris Davies’s Gwalia Deserta XXXVI into the rocking Turn No More, while the Beaufort male voice choir sing Take Me Home.

The risk of romanticising the past hangs heavy on this record, but tracks such as The Pit bring things back to earth, detailing the “three feet and six inches” of working space and the 80 degree heat. So does the chorus of Progress (“I believe in progress”), the melancholic double meaning captured perfectly by Camera Obscura’s Tracyanne Campbell. Willgoose didn’t want to impose a stronger political message on the music, because “it’s much more powerful if you leave ambiguity in –if you’re too earnest it doesn’t matter how correct your message is”.

He’d prefer that the echoes of the past in this record help us think about the present, like how the destruction of the unions in the 80s has a legacy in working conditions today. After the Tory majority in 2015, and last year’s Brexit vote, this project felt even more vital. “Watching it become more relevant, as more dominoes fell… it felt important to get on with it”, he says.

Half an hour before showtime, the institute is buzzing. The NUM’s Wayne Thomas and Ron Stoate are here, who Willgoose interviewed for the album; solid men in polo shirts who survived the miners’ strike, they’re still youthful now, which propels the past to the present. Stoate thinks the record’s “really good – mining songs before this were solemn and about dust and dying in your hospital bed”. Thomas agrees. “For a young man to come in from outside and really get to know the people and piece the story together – there’s real sincerity there.”

Both men believe the people of the valleys have been hoodwinked by politicians in recent years. “The Leave vote was that bloody bus. £350m to the NHS – so many people voted for that,” Stoate rails. “And as for immigration! People going, ‘Bloody Poles coming here, taking our jobs.’ Down the mines, we worked with Poles all the time. Lithuanians, Latvians, all of them!” Wayne nods. “Locally, nationally, internationally, there’s been a smashing of that knowledge base, those memories.” Then he shrugs. “You can only hope things will get better.”

Public Service Broadcasting take the stage at 8.30pm. The show is rousing and moving, grown men welling up at the National Coal Board’s 1960s recruitment campaign adverts, as well as songs about the conquering of Everest and the first orbiting of the moon – all night, you see men transported back to their childhoods, in full voice.

Seven hours later, Blaenau Gwent returns its Labour MP, Nick Smith, with 58% of the vote, and the Ukip candidate drops from second place to fourth. Willgoose spends the night at a nearby Premier Inn, in shock, with the words of a fan who grew up near Ebbw Vale still ringing in his ears. “He said the gig was a strange sensation, like having a band speak directly for him… and if we have helped people have their voices heard, in a tiny way, then that’s great.” And how does he feel about the election result? “It’s a total mess, but maybe it’s the start of a new generation finding their voice, realising they have the chance to make a difference.”

Every Valley is released by PIAS Recordings on 7 July