On a patch of grass on an estate, a kid attempts a dicey BMX stunt in front of his mates. In a barber’s, a hairdresser puts the finishing touches to a spiky mohican. Outside a Jobcentre, teenagers kick a ball around. In front of pebble-dashed terraces, Ford Cortinas sit in a long line. Elsewhere, an old man sunbathes in nothing but pants, socks and shoes.

To visit the online People’s Archive is to travel back in time, to a Britain before smartphones made snappers of us all. Here you’ll be reminded of some the country’s most dazzling subcultures – from female punks to floppy-haired Spike Islanders – and get the sort of insight into working-class life that only the best documentary photographers can provide. Yet none of these images were taken by people who consider themselves photographers. Often holiday snaps, they were shot by amateurs, one great picture among countless humdrum efforts. This month, however, they will go on display in London, alongside work by far more established names.

You might take 500 photos and end up with one photo that really captures the time

The project was never intended to take off. Paul Wright was an office worker in Manchester, his hands full looking after two small children, when he started posting the odd photograph he found online – he admits he didn’t realise how copyright worked back then – to his Instagram page. “Alongside pictures of my family,” he laughs. This blossomed into the British Culture Archive, a dedicated Instagram and Twitter account for all the shots he was finding online. It soon found fans in the likes of Johnny Marr and Robert Carlyle. The latter actually got in touch to say: “Thanks for all the beautiful images. Haunting, evocative, vibrant … Love them all.”

‘I get messages asking why I don’t feature any middle-class culture’ … Widnes. Photograph: courtesy of the People's Archive

“I was pretty chuffed with that,” says Wright when we meet today in a London cafe. “It made me realise I must be doing something right.” Wright’s plan was to focus on photographers whose work he thought had been overlooked or forgotten. But soon, people who wouldn’t dream of calling themselves photographers were getting in touch. “They would say things like, ‘This is us when we were punks in 1977.’ At first, I didn’t know what to do with them all, but then I had an idea.”

So the People’s Archive was born – and it can be quite a thrill to have an image selected. “I love the idea,” says Jacqui Pollock, an NHS worker who submitted her late father’s picture of her family out on the Salford streets. You can see why the shot caught Wright’s eye: a row of mischievous looking tykes perch on a car bonnet clutching sweets, the yellow stain on the picture adding an extra layer of authenticity. Wright chose it as the lead image for his exhibition, which would have surprised the man who took it.

“He was a giant of a character, but he wasn’t a photographer,” says Pollock of her father. “He was a window-cleaner.” How would he react to his work being shown alongside that of established photographers? “He’d probably say, ‘Fuckin’ yuppies, the lot of them!’ But he would be proud, really. Then he’d turn up and cause chaos.”

Jacqui Pollock and family in Salford, from the People’s Archive on Instagram Photograph: British Culture Archive

Being included in the archive has prompted Pollock to reconsider the photograph. “I love that my parents got how special childhood is, that we had freedom and space to play.” She talks of her “bonkers Dad” who “really lived his life – despite many things that could have dragged him down, like breaking his back after falling off a building cleaning windows. He had a wisdom and playfulness that was infectious. He never allowed himself to lose his childlike ability to have fun. He was my hero.”

This is exactly what Wright wants: it’s more than just a nostalgia trip. “People say you shouldn’t look back, but it can be good. Maybe you had ideas for your life back then that haven’t panned out. I’ve had messages from people saying the archive spurred them to change what they’re doing.” Was he surprised by the quality of the shots people had squirrelled away? “Yeah! But it’s like if you go on holiday with your mates – you might take 500 photos and end up with one that really captures the time.”

More than a nostalgia trip … Hulme. Photograph: courtesy the People's Archive

One theme of the archive is a celebration of working-class culture. Wright’s dad was a fireman who went on strike in the 1980s and he grew up with a fascination for the turmoil the country endured in that decade. “I get messages asking why I don’t feature any middle-class culture,” Wright says. “But I don’t really know what that is. If someone wants to send me pictures of, say, the badminton casuals or whatever, then fine. But this is what I know.”

Although Wright wants the British Culture Archive to be politically neutral, he knows how toxic and divisive these times are. In such a climate, images celebrating working-class culture and multiculturalism really resonate, offering a reminder of a time when communities had stronger bonds.

Take Richard Davis. His photos of the 1980s brutalist architecture of the Hulme area of Manchester, long since demolished, will feature in the exhibition. Davis says his photos generated a little local interest at the time but since the British Culture Archive shone a spotlight on them he has found wider recognition, including a book deal. “Needless to say this has really reignited my passion in photography,” he says. “So much so that I’ve set up my darkroom again.”

Tish Murtha gained a similar leg-up: her black and white images of life in Newcastle and the north east of England were woefully overlooked during her lifetime. “Because she was a female photographer in the 70s, from a working-class background, I don’t think she fancied her chances approaching publishing houses,” says Wright.

Tish Murtha’s Kids jumping onto Mattresses, 1980 © Ella Murtha, All rights reserved. Courtesy of Ella Murtha and The Photographers’ Gallery Photograph: copyright the artist and courtesy Ella Murtha / The Photographers' Gallery

Murtha died in 2014, but her daughter Ella made it her mission to get her work the recognition she thought it deserved. She recently published a book of her mum’s work called Youth Unemployment. “Paul called it his favourite book of 2017 and I suddenly started getting loads of new followers. A whole new audience was discovering my mam’s work. Paul is doing it purely for the love of photography and the desire to preserve memories and culture for future generations.”

Wright wants to run the British Culture Archive – and it’s People’s Archive offshoot – full time. He has raised £12,000 through crowdfunding, and is eyeing the Lottery Heritage Fund and other sponsorship options. Ultimately, he’d like to secure a permanent space in his home city, where he can put on guest exhibitions and workshops for local kids. He remembers his own talent being snuffed out by his teachers, and wants to stamp out the notion that photography is only for certain people.

So he’ll keep on doing what he does best: scouring the web for hidden treasure as soon as his kids have been put to bed. “It’s not like work,” he says. “It’s a labour of love.”