Over the past few years, there has been a distinctly Scottish flavour to the Turner prize. Last year, the winner was Glasgow-born Susan Philipsz, for a sound installation she created in the seedy, dank shadow of a bridge over the Clyde. The year before, it was Richard Wright, for his intricate, painstakingly made wall paintings; he did his masters at the Glasgow School of Art and still lives in the city.  This week, the work of all four shortlisted artists goes on show at the Baltic, Gateshead – and two are Glaswegian: Martin Boyce, whose sculptures do fearful things with modernist interior design; and Karla Black, who uses lipstick, pastel-coloured candles, eyeshadow and sugar paper as her materials. Artists based or born in the city who have been shortlisted in the recent past include Jim Lambie, Christine Borland, Cathy Wilkes, Lucy Skaer and Nathan Coley. There have been two further winners in Douglas Gordon and Simon Starling.  If the Turner prize provides a rough-and-ready compass bearing for visual art in Britain, the needle has for some time been twitching towards this grandiose, grandiloquent, sometimes rough-and-ready city. Why? A clue can be found in the first issue, from September 1991, of the contemporary art magazine Frieze. It contains an interview with three artists in their early 20s. They have just graduated from the Glasgow School of Art. They are articulate, cocky and funny. They seem to know, with an intense certainty, that they are artists, not just art-school graduates. One writes off, with breathtaking chutzpah, a then-prominent school of Scottish painters as "a tiny, unimportant part of the international art world". Another, while admitting such a formulation is crass, says their own work has "more to do with hip-hop and the Face than Constable". These young guns are Douglas Gordon, Nathan Coley and Martin Boyce. Five years after the interview, Gordon – now best known for film works such as 24-Hour Psycho and Zidane – won the Turner prize.  Something very particular happened at the Glasgow School of Art in the late 1980s. A group of young Glaswegians – including Coley, Gordon, Boyce and Borland – began to study a new course: environmental art, led by the now-retired David Harding. "They were confident and confrontational and questioning‚" says Harding, when we meet in his flat among the elegant terraces of Glasgow's west end, a picture of Bob Dylan on the wall, a Peter Seeger LP propped on the piano. "I was astonished by their articulacy."  The course was not traditional painting or sculpture. It was, say its graduates, about ideas. The context for making work was as important as the work itself. The department was not based in the Charles Rennie Mackintosh-designed main building, but in a former girls' school that was used as a site for making work. "It was an amazing place," says Harding. "There were basements with 50 children's sinks in them, history books lying around in piles. There were attics, strange, devious, different rooms. An Escher-like staircase. One half of the school was locked off and forbidden. Of course, the students broke in."  The students were required to do art projects outside the school, to find sites, negotiate with owners. "They began to be wheelers and dealers. They had to forage in other departments to get access to dark rooms, printing facilities. They had," says Harding, "a piratical attitude."  It was an attitude in tune with the times. As Coley says, "We were children of Thatcher. Doing it for yourself was in the air. It seems crazy what we did now: we'd get money for international projects out of a combination of ignorance and blind confidence." Down south, a group of artists – many of them graduates from Goldsmith's, London – were also operating in a new way. But if some of these Londoners, quickly dubbed YBAs, were selling to Charles Saatchi and making work with the quickfire cheerfulness of billboard ads, that certainly wasn't happening in Glasgow. The YBAs were entrepreneurs; the Glaswegians were scavengers. Their work was more lyrical, less immediate.  I meet Coley at the Glasgow Sculpture Studios, a hive of quiet industry with its neatly organised metal and wood workshops and its 45 artists' studios. Coley's trim space is hung with work-in-progress: a series of photographs with certain areas blanked out with gold leaf: new work for a solo show in London next year. There was nothing magical about his and his friends' success, he says. "It was really, really hard work." It is clear, though, that there was a set of propitious circumstances that affected not just these young people in Glasgow, but the art world internationally. Moira Jeffrey, art critic of the Edinburgh-based Scotland on Sunday newspaper, points out that the artists emerged "at a politically desperate moment. We forget how horrible the late 1980s were. It was the dwindling Tory era. In Glasgow, the situation was economically dire, but there was a good education system and student grants – and you could live cheaply." There was also, she says, a certain power "in the fabric of this city, built on sugar, ships and slavery. It is a very ambiguous heritage, but incredibly grand."  Perhaps the most important factor, though, was the web of relationships established between those students from the late 1980s – a way of interacting that seems to have set the tone for the Glasgow art world since. According to Harding: "We partied a lot. Drank a lot. And with people like Douglas, Martin, Nathan, I'd go to their weddings, their children's christenings, birthday parties, and still do."  The students fell in, and sometimes out, of love with each other. They mostly lived near each other, up on the windy heights of Garnethill near the art school. Gordon went out with Borland, and shared a flat with Katrina Brown, now a curator, who went out with Coley (the latter couple are still together). Brown is now director of The Common Guild, a gallery based in a house in Glasgow belonging to Gordon. Later, Gordon was best man at Richard Wright and Sarah Lowndes' wedding; she now lectures at the art school, and has written a study of the city's art scene called Social Sculpture.  After graduating, a rite of passage for many was to sit on the committee for the artist-run gallery, Transmission, which had been set up in 1983 to instigate all kinds of international projects. According to Coley, "There was a mixture of gallusness, confidence, and being a bit wide." Gallus is one of those almost untranslatable Scots words that hovers somewhere between uncompromising, bold, swaggering and unstoppable. Harding uses it, too. "They were gallus. They were going to prove that they could do something." They also, crucially, helped each other. Coley says, if a curator comes to Glasgow to see you, "There's an unwritten rule that you introduce them to someone else, too."  Borrow a book from a pop star  It wasn't a paradise; it was a struggle. There was some public funding, and the artists were often helped by unsung, visionary civil servants. But when the city's Gallery of Modern Art opened in 1998, it totally – and scandalously – ignored the new wave of Glasgow artists. Brown thinks that that early institutional blindness has been damaging, particularly to Glasgow's ability to support a market for contemporary art. "If your city gallery is saying Beryl Cook is an important artist, maybe you don't want to buy a Douglas Gordon," she speculates. The economics of the scene, she says, are "fragile".  This autumn, Sorcha Dallas, a Glasgow gallerist, announced she was closing her doors, citing the combination of the removal of the Creative Scotland funding that allowed her to visit international art fairs, and the recession. "It's not that there aren't rich people," says Dallas. "It's just that they choose to spend their money elsewhere. People here would be more inclined to buy a Jack Vettriano than a Douglas Gordon." Environmental art graduate Toby Webster, who co-founded The Modern Institute, a commercial gallery that has been of huge importance in promoting the work of the major Glasgow artists, says it is important for him to be in the city, "two minutes away from where the artists work". But most of his buyers live elsewhere. Perhaps the scene is so close-knit because its leading lights remain relatively unsung in their own city.  Is the Glasgow scene a flash in the pan, a one-off alchemical combination of people, place and time? The scene has, of course, changed. Different kinds of students have been attracted by the city's rising reputation, coming from England and abroad (at first, they were nearly all natives). Some of the early wave have stayed or drifted back to Glasgow, Borland, Boyce, Coley and David Shrigley all live here, no longer young guns, but established artists in their 40s. Jeffrey believes pop musicians set an important example, showing that you didn't have to move to London to make it. "It set a paradigm. Stephen Pastel, of the Pastels, had an international career, and he worked in a library. You could go and borrow a book from your favourite pop star. The people you'd see in the pub were selling records all over the world."  Harding has seen great changes to art-school education, funding cuts chief among them. His department was merged with sculpture. A decade ago, he retired. But he still has faith in students, he says. According to Jeffrey: "I had a period where I worried that Glasgow School of Art would become a posh finishing school: but people come here and start behaving like Glaswegian artists."  I ask Sarah Lowndes if she believes Glasgow will continue to produce Turner-shortlisted artists, or whether we are reaching the end of an era. She reels off younger but already established names such as Torsten Lauschmann and Lorna Macintyre; and mentions younger artists, too, "bright sparks" such as Tom Varley and Rebecca Wilcox. "There's a network that's not predicated on commercial success, but on the idea of community," she says.  And now for a song  In search of a younger scene, I head to a gallery called the Duchy, carved out of an old shop near St Mungo's Cathedral; it's a slightly ramshackle part of the city being smartened up for the 2014 Commonwealth Games. Here, Glaswegians Lauren Currie, 26, and Ainslie Roddick, 24, are putting the finishing touches to their new show. The two – Currie, a graduate of Dundee's Duncan of Jordanstone college; Roddick, from the Glasgow School of Art – met when they were working in a deli, and set up the Duchy out of a conviction, says Currie, that "there needed to be somewhere for our generation of artists".  They turned next door into studios and rented them out to raise income for the gallery. They converted the space themselves. These immensely self-possessed young women, in their energetic but co-operative way, seem to have much of the spirit of their predecessors. "The older artists are accessible," says Roddick. "They go to shows, and there's something that keeps them here. It has given people a confidence that you can stay in Glasgow as an artist." This is a not-for-profit space; they are not interested in running a commercial gallery. "It's not needed," says Roddick firmly.  Towards the end of our conversation, Harding says something out of the blue: "The singing – that was really important." There was always lots of singing, he says. Every year, he would host a Burns supper in his flat. All the guests were expected to recite a poem or song. There is something remarkable about imagining these cool, perhaps rather belligerent, young artists standing up and singing, say, Scottish songs from their childhoods. Harding remembers one night in particular: "Before Douglas started singing, he said, 'I want to tell you a story. A curator was asking me: what were you taught in Glasgow? Where did it all come from?' And Douglas said, 'Singing.'"  • This article was amended on 20 October 2011. The original said Moira Jeffrey was art critic for the Herald newspaper. This has been corrected.
Why does Glasgow keep producing so many Turner prize winners and nominees? Could it all be down to this man? Charlotte Higgins investigates