In 1967, while working with the Swiss photographer Jean Mohr on A Fortunate Man, a book about a country GP serving a deprived community in the Forest of Dean, Gloucestershire, John Berger began to reconsider what the role of a writer should be. “He does more than treat [his patients] when they are ill,” Berger wrote of John Sassall, a man whose proximity to suffering and poverty deeply affected him (he later committed suicide). The rural doctor assumes a democratic function, in Berger’s eyes, one he describes in consciously literary terms. “He is the objective witness of their lives,” he says. “The clerk of their records.”

The next five years marked a transition in Berger’s life. By 1972, when the groundbreaking art series Ways of Seeing aired on BBC television, Berger had been living on the Continent for over a decade. He won the Booker Prize for his novel G. the same year, announcing to an astonished audience at the black-tie ceremony in London that he would divide his prize money between the Black Panther Party (he denounced Booker McConnell’s historic links with plantations and indentured labour in the Caribbean) and the funding of his next project with Mohr, A Seventh Man, recording the experiences of migrant workers across Europe.

This is the point at which, for some in England, Berger became a more distant figure. He moved from Switzerland to a remote village in the French Alps two years later. “He thinks and feels what the community incoherently knows,” Berger wrote of Sassall, the “fortunate man”. After time spent working on A Seventh Man, those words were just as applicable to the writer himself. It was Berger who had become a “clerk”, collecting stories from the voiceless and dispossessed – peasants, migrants, even animals – a self-effacing role he would continue to occupy for the next 43 years.

The life and work of John Berger represents a challenge. How best to describe the output of a writer whose bibliography, according to Wikipedia, contains ten “novels”, four “plays”, three collections of “poetry” and 33 books labelled “other”?

“A kind of vicarious autobiography and a history of our time as refracted through the prism of art,” is how the writer Geoff Dyer introduced a selection of Berger’s non-fiction in 2001, though the category doesn’t quite fit. “To separate fact and ­imagination, event and feeling, protagonist and narrator, is to stay on dry land and never put to sea,” Berger wrote in 1991 in a manifesto (of sorts) inspired by James Joyce’s Ulysses, a book he first read, in French, at the age of 14.

Berger’s influence in the literary and wider artistic worlds is a little easier to measure. “He is the lodestar of the contemporary literary experience,” the Irish novelist Colum McCann tells me. “I cannot imagine my bookshelves without him. The other writers would collapse.” Susan Sontag described him as “peerless” for his ability to merge “attentiveness to the sensual world” with “the imperatives of conscience”, though Berger himself prefers to be described, simply, as “a storyteller”. Social and political commentary, subjective response and aesthetic theory are the ­basic elements of much of what he writes – but it all begins with seeing.

When I arrive, wet, to meet Berger at a house in Paris one recent gloomy morning, he looks concerned. “You’re cold!” he says, urging me to sit down by the radiator while he disappears into the kitchen to make coffee.

***

Born in Hackney, London, in 1926, John Berger was sent to boarding school at the age of six. He was away from his parents for ten months of the year, an experience he has described as “monstrous”. “That school in Lindsay Anderson’s If . . . was the Côte d’Azur compared to those places,” he told the Guardian’s Sean O’Hagan in 2005.

“I was, in a way, alone in the world,” he says as we settle down at the dining room table. “I don’t say that very pathetically. I just took it as a fact of life. But being like that means you listen to others, because you are seeking landmarks to orient yourself in relation to – and, unlike what most people think, storytelling does not begin with inventing, it begins with listening.”

Berger left St Edward’s School in ­Oxford when he was 16. He refused an officer’s commission with the Oxfordshire and Buckinghamshire Light Infantry, after which he was posted to Ballykelly, Northern Ireland. In 1946, he enrolled at the Chelsea School of Art under the tutelage of Henry Moore, whom he rounded on less than a decade later, referring to the sculptor’s work in a review in the New Statesman as a “meaningless mess”. Though he rejects the title of “art critic” because it “suggests somebody deciding how many marks out of 20 to give”, he began to write regularly about art and culture for the NS and other publications in the early 1950s.

“It wasn’t easy,” he recalls. “Every Monday at 11am, I would go up the stairs to the office with my pages and fight to get them to publish what I brought in.” The piece on Moore, for instance, provoked outrage among NS readers. (Stephen Spender wrote to the editor that Berger’s work was like “a foghorn in a fog”, to which Berger duly replied: “Assuming that a poet always picks his images carefully, I must thank him for the compliment. For what, in a fog, could [be] more useful?”) This was an art world governed by connoisseurs, collectors and “experts”, the very crowd whom Berger later denounced in Ways of Seeing as marshalling “the nostalgia of a ruling class in decline”.

“It wasn’t so bad,” he says of his first regular writing job with the NS. “There was coffee.” The magazine’s then editor, Kingsley Martin, was “difficult to describe because there aren’t people like that any more: very open, tall, worn face, in his way a militant and a puritan. I respected him long before I wrote for the paper.”

One day, Martin called Berger into his office. “He said, ‘Look, John, I’ve decided I want to learn to draw. I’m retiring now. Do you know anybody who could help me?’ And I said, ‘Yes, let me try, I think I can.’ So, every ten days or so, I would visit Kingsley in his flat, which was off the Strand, and encourage him. This considerably changed my position on the paper, because when I went in with the next little piece and there was another argument (which I wasn’t ­winning), I would say, ‘Could I go round and see Kingsley and see what he thinks?’ He didn’t always support me but most of the time he did – and my life became easier.”

Berger spent his years in London among political refugees, European Marxists such as the Hungarian art historian Frederick Antal and the French-born painter Peter de Francia, who had fled the Nazis in Belgium. “The hierarchy of British authorities did not impress them because they’d seen something harder and fought it,” Berger says. “I think I learned from them, not exactly confidence, but a kind of indifference, a refusal to be intimidated.”

In 1962, after four years in rural Gloucestershire (where he first met and became friends with John Sassall), Berger moved to Geneva, where he was introduced to Jean Mohr by the Swiss film-maker Alain Tanner. Berger wanted to learn to take photographs and Mohr had offered to teach him. “I quickly lost interest,” he recalls. “I noticed that when you take a photograph, you stop looking at what you’ve shot. I was more interested in looking. I think I gave my camera away.”

Berger, who is 88, is wearing a navy fleece and baggy corduroy trousers, his smooth white hair standing upright. He concentrates intently on our conversation. Too intently, perhaps: he has left the gas burning on the stove.

“Oh, merde! Oh, no!” he calls out, hurrying back into the kitchen.

“Remember that, up to the age of 30, I was a painter,” he says, scrubbing the base of the blackened kettle with hot water and soap. “I’d spend my days in a room I called a studio, drawing and painting. I don’t paint any more but I draw frequently . . . I live enormously through my eyes. The visible is simply a very important part of my experience of being in this world.”

In 1974, he relocated to the French hamlet of Quincy, nestled in the Alps with a clear view of Mont Blanc, living and working among agricultural labourers – or “peasants”, the term Berger prefers and uses without the slightest whiff of urban condescension. He remained in Quincy with his son Yves and his American wife, Beverly Bancroft (who died in 2013) for more than 40 years.

Today Berger continues to draw, speak publicly and write what he calls “notes”. Surprisingly, there has been no ­biography. The facts are often difficult to secure – something that may not be accidental. “If someone asked, I’d say, ‘I can’t stop you but I’m not collaborating.’” I ask why. “I’m all for the diffusion of what I’ve written,” Berger says, “but my own story doesn’t interest me.” He pauses. “There’s a risk of egocentricity. And to storytellers, egocentricity is boring.”

***

The house where we meet, in a suburb on the outskirts of ­the city, belongs to Nella Bielski: a writer and actress born in the Soviet ­Union and an old friend of Berger’s. “How long have you been in Paris?” I ask her, over a lunch of smoked eel, blini, devilled eggs and lamb’s lettuce salad. “Fifty years,” she says. “The longer I stay, the more Russian I feel.”

As the water boils for a second pot of coffee, Berger lays out a series of illustrations that have arrived in the morning’s post (along with his daily newspaper, the communist L’Humanité). “They’re by a friend of mine, a cartoonist of Turkish origin called Selçuk Demirel,” he explains, leafing through the drawings, responses to the massacre at Charlie Hebdo. “He wants me to imagine a text to them.”

I had been due to meet Berger at the end of last year at the launch of his Collected Poems, published by the Teesside-based Smokestack Books, but he was forced to cancel because of a painful back. “At my age, that’s nothing,” he says. “It doesn’t get worse. Sometimes it gets better. I’ve used it like hell – haymaking, and so on.” When I remind him of our missed rendezvous in Middlesbrough, a town formerly known for its steel production, he tells a story.

“When I was, oh, in my mid-twenties, I got permission to draw and paint at a ­foundry in Croydon, which cast bells for churches. It was an incredible experience,” he says. “In a foundry like that, because of the risk factor, the complicity between the workers is amazing to see.” I ask how they responded to the young guy loafing in the corner with his easel. “Very well. I went every day during the same hours as the shift. They were working and so was I.”

Among the many pictures on the wall, there is a small watercolour depicting street acrobats in Livorno, Italy. “That’s more or less how I painted at the time,” he says. The image is dynamic – realist and a little romantic but not naturalistic. Along with steelworkers and street performers, the artist Berger painted welders, builders and fishermen. Though his technical approach differed, the choice of subject matter suggests the influence of Caravaggio (“the first painter of life as experienced by the popolaccio, the people of the backstreets”), Picasso and the French cubist Fernand Léger. Berger credits Léger’s treatment of “cities, machinery [and] workers at work” with creating “a new kind of beauty” – a forward-facing art, in “symbolic contrast with the hypocrisy and corruption of the bourgeois world that plunged with self-congratulation and inane confidence into the 1914 war”.

An interest in “the lower depths, the under­world”, led Berger to visit a series of abattoirs in London, Paris and Istanbul in the 1970s. “I didn’t directly write about it,” he says. “I just needed it as part of my awareness of the world. Interestingly enough, the slaughterhouse in Istanbul was the least ruthless of them all. The idea of sacrifice still existed somewhere in the procedures.”

It is difficult to imagine Kenneth Clark, the tweedy aficionado whose stately TV series Civilisation provided the stimulus for making Ways of Seeing, engaged in clandestine research amid the bloodshed at an ­abattoir. “Clark was a good man in his way,” Berger says. “I knew him and we got on quite well. But he totally represented the connoisseur explaining to the populace this is how it is. Ways of Seeing was a collaboration. We wanted people to ask questions. It was the opposite of the ivory tower.”

The series of four 30-minute programmes and the book that followed were an attempt to demystify the history of art and identify the prejudices we unconsciously impose on the act of looking. It has been a staple of ­British art school education ever since.

Berger argued that a critical obsession with form and technique removed paintings from “the plane of lived experience”. Technology – mechanical reproduction – created a “visual language” out of images previously confined to churches and galleries, and with it new possibilities for both control and liberation. (On the last page of the book, following a print of Magritte’s On the Threshold of Liberty, a painting of a cannon facing various conventional canvases and images, are the words: “To be continued by the reader . . .”)

Even in the age of Tumblr, Pinterest and Google Images – not to mention the endlessly reproducible objets licensed out by artists such as Jeff Koons and Damien Hirst – the book remains relevant.

“Adults and children sometimes have boards in their bedrooms or living rooms on which they put pieces of paper: letters, snapshots, reproductions of paintings, newspaper cuttings, original drawings, postcards,” Berger wrote in Ways of Seeing. “Logically, these boards should replace museums.”

“That was a long time before digital,” he says now, laughing. (Though Berger uses email only on occasion and prefers to speak on the telephone or to send letters, I had noticed that he had recently been using an ­iPhone. ­Sample text message: “Awaiting u. Laughs & wishes best, John.”) He argues that the internet, like the language of images, “possesses the same duality of possibilities, one opposed to the other, as both an instrument of control by the forces that govern the world – that’s to say, financial capitalism and what I call ‘economic fascism’ – but also for democracy, associating directly with one another, responding in a spontaneous but collective way”.

***

Midway through the afternoon, we head out to run a few errands. It is still raining. “Even after 30, 40 years, I still have a very strong English accent,” Berger says, as the cashier wraps up two bottles of white wine at the épicerie. “It’s the same thing when I go to London, which isn’t often. I’ll be in a pub and someone will ask me, ‘Where are you from? You speak English very well.’”

I walk back with the groceries and sit with Bielski, who is watching a Rossellini film and chopping vegetables, while Berger attends a physiotherapy class, for his back, at the local municipal pool.

Reading John Berger in 2015 can be disconcerting, not only stylistically – he tends to write in hefty sentences, building an image or idea the way that a draughtsman adds lines to a sketch – but in terms of what we expect to encounter. Contemporary fiction – think Åsne Seierstad’s Bookseller of Kabul or John Boyne’s Boy in the Striped Pyjamas – suggests that empathy and imagination can help the reader understand hardship and injustice. Berger’s is a more materialist outlook. He insists on action.

After A Fortunate Man and his 1972 Booker victory, Berger’s focus began to shift from industrial workers, Léger and Picasso, to rural peasants, Van Gogh and Millet – earlier painters whose work, he claimed, spoke to the present. “Unlike William Morris and other romantic medievalists,” Berger wrote of Millet in 1976, “he did not sentimentalise the village . . . [He sensed] that the poverty of the countryside would be reproduced under a different form in the poverty of the city and its suburbs, and that the market ­created by industrialisation, to which the peasantry was being sacrificed, might one day entail the loss of all sense of history.”

So, art has a historical function, “entirely opposed to art for art’s sake”. It restores to memory that which has been, or is being, eliminated. “During the second half of the 20th century the judgement of history [was] abandoned by all except the underprivileged and dispossessed,” he wrote in a 1978 essay on photography. The focal point, or anchor, for Berger, was the village.

In a 1936 essay, Walter Benjamin identified two kinds of “storyteller”: “someone who has come from afar” and “the man who has stayed at home, making an honest living, and who knows the local tales and traditions”. Berger represented both during his years in the Alps, writing Pig Earth (1979), Once in Europa (1987) and Lilac and Flag (1990) – a trilogy of novels about the disappearance of the European peasantry and their culture. Perhaps what connects Ways of Seeing with the lesser-known trilogy is an attempt to reveal what would otherwise remain concealed. “What makes me write is the fear that if I do not write, something which ought to be said will not be,” he explains. “Really, I’m a stopgap man.”

I ask whether the desire to live among people who had access to their shared history lay behind the move to Quincy. “It’s what I discovered when I got there,” he says. “The past is very present to me and has been for a very long time. I first became aware of this quite intensely when I was a teenager, because of the First World War. You see, I think that the dead are with us.”

Berger’s father, Stanley, served as an infantry major in the trenches during the 1914-18 war and was awarded the Military Cross. He remained in the army for a further four years until 1922, organising war graves for the British dead. It was Berger’s mother, Miriam, a working-class woman from ­Bermondsey, London, who helped him to return to civilian life.

“What I’m talking about now is a very ancient part of human awareness. It may even be what defines the human – although it [was] largely forgotten in the second half of the 20th century. The dead are not abandoned. They are kept near physically. They are a presence. What you think you’re looking at on that long road to the past is actually beside you where you stand.”

***

Before I leave, and having shared several glasses of wine, Berger shows me a box. It is a beautiful object. It has a lid, under which are smaller boxes filled with matches. Each one has a different songbird painted on the top. “Somebody gave me this from Russia,” he says, almost in a whisper. “I was thinking, ‘I want to give it to Rosa Luxemburg, who loved birds and flames.’ So I’m writing a text to send it to her.” Luxemburg, the Polish-German revolutionary, was shot and dumped in a Berlin canal in 1919 but I say, “I’m sure she’ll love it!”

He laughs. Something that surprises people who have read but never met Berger in person is his extraordinary warmth. One reason he has cited for leaving England – other than his hatred of the “class awareness . . . so embedded in British comportment and judgement” – is that the stiff-upper-lipped English considered him “indecently intense”. When I mention this, he simply says that while he can be “angry and outspoken . . . hospitality seems to me to be an incredibly important human capacity. And the first rule of hospitality is to accept the presence of somebody and exchange.”

“Nelska” and “Jeanie” – as Bielski and Berger affectionately call one another – are winding down. Bielski emerges from the kitchen with a bottle of Kir. The conversation turns to politics. With Walter Benjamin’s essay in mind, I mention the indignados (“the outraged”) – the movement of students, the retired, and unemployed public-sector workers whose campaign of personal storytelling led to the creation of the left-wing party Podemos in Spain. Likewise the women of Iran, Turkey and India, for whom public expression has been a vital tool in the fight against ingrained misogyny and violent abuse.

“I follow that and underline it completely,” Berger says, rising to welcome Bielski’s granddaughter Helena, a student at a university in Paris, into the house. “And it’s very important to emphasise how it is something new, opening up a scenario that we can’t quite imagine because it’s very different from those that we know.”

In 2009, Berger donated his personal archive – a collection of letters, drafts and sketches accrued over a lifetime and lovingly stored by his late wife, Beverly, in a stable at Quincy – to the British Library. A few days after I met Berger in Paris, Tom Overton, the researcher who was responsible for cataloguing the archive, explained how the process had worked. “I’d find something and have no idea what it was,” he said. “I’d scan it in and email it over to Beverly. Some time over the next week, often early in the morning or late at night, I’d get a phone call. A familiar voice would begin: ‘Can I tell you a story?’”