It is a dozen years since Chris Ofili deliberately stepped away from the art worlds of London and New York and moved to Trinidad. At the time Ofili was famous in the popular imagination for two things. He had been, aged 30 in 1998, the first black winner of the Turner prize, in part for his indelible tribute to Doreen and Stephen Lawrence, No Woman, No Cry. And he had achieved international notoriety when New York mayor Rudolph Giuliani closed down a show at the Brooklyn Museum of Art because it featured Ofili’s (beautiful) painting of the Holy Virgin Mary, which employed spherical lumps of elephant dung, his signature material, and a host of angels that on close inspection were cut-outs from porn magazines. Ofili was too smart, and too good an artist to want either of those lines of notoriety to define him. So he moved in part to escape those pigeonholes – “black British artist”, “pachyderm shit Giuliani guy” – to make things new.

He first went to Trinidad in 2000 to host a workshop in Port of Spain, along with his great friend from Chelsea art school days the Scottish-Canadian painter Peter Doig. They were both entranced by what they found on the island, and went back a dozen times, before separately buying land and moving permanently four or five years later. I remember talking to Doig about that shared decision in an interview, not long after they had gone, and him being still in thrall to the sheer strangeness of exploring the island with Ofili on that first trip, partly by canoe. Looking back now, Ofili, born in Manchester to first generation parents from Nigeria, lights up in a similar way recalling that voyage of discovery.

It's been extraordinary working with the weavers. For them it's really a two and a half year meditation

“Moving to Trinidad was a great experiment,” he says, with the easy smile of a man for whom the hypothesis delivered. “I never knew what it would do to my work. Or even if it would be accepted by people, and not be seen as me just falling off the edge of the earth.”

Why did it seem like the only thing to do?

“As cliched as it sounds,” he says, “that first visit with Peter really was euphoric. Every morning you had the feeling that you were right there on the edge of what you want to be creative. You don’t understand it, necessarily, but you know that it’s the food that you need. You want to stuff it into yourself.”

Ofili had sensed that kind of feast once before, in 1992, on a visit to Zimbabwe, which became a kind of pilgrimage to study ancient cave paintings. That trip had resulted in him packing balls of elephant dung in his suitcase, aide-memoires of all he felt. Not sure what to do with them when he got home, he put them on a display at Brixton market, before making them emblematic of a trippy pan-Africanism in his phosphorescent English paintings (he managed to establish a regular supply from London Zoo).

No Woman No Cry, Ofili’s tribute to Stephen Lawrence’s family, 1998. Photograph: Rosie Greenway/Getty Images

In Trinidad, Ofili didn’t just want to bring the otherworldly emotion home in his suitcase; he wanted to go there and live among it. “It’s hard to describe,” he says. “I was like, nostrils wide open. I knew this might break everything that I had done before or it might remould it. But I knew I had no option but to go with it, or live with the fact you had basically suffocated yourself.”

He moved out to Port of Spain with his new wife, Roba El-Essawy, whom he had met when she was a singer and songwriter in a London hip-hop band called Attica Blues. Their two children, a boy and a girl, now nine and six, were born on the island. Ofili asked his closest friend, the architect David Adjaye, to build a house and a studio for the family in the jungle above a favourite beach. In the meantime, while the plans were being carefully laid, he painted most days in a decrepit cottage that clung to the hillside 10 minutes from downtown Port of Spain. The set-up was about as far as he could get from the Young British Artist conceptual world with which he had been inadvertently associated: no studio assistant, no technical support, no sense of the art market “constantly nipping at your heels”, and no glitter or elephant dung. Just him and the canvas.

“I always wanted to do that. I did like the idea of having only paint and a surface. And I think it is working for me. I am not that interested in the question of whether I am making better things than I was. Just that I don’t feel as limited as I did 12 or 15 years ago.”

Ofili has always had an edgy, shape-shifting relation with post-colonial politics, searching the present moment for resonant mythology. His most acclaimed work since his chosen exile has been his Blue Devils series, which took a Trinidadian carnival tradition of men coming down from the hills body-painted blue, to spread mischief and intimidation, and viewed it partly in the context of the relations between police and young black men in western cities, to after-dark stop-and-search.

The sense of partial mystery in those paintings, of known unknowns, is ever present in his work from the island. It’s there, he says, “because Trinidad never really fully reveals itself. They have not set themselves up in the way that other Caribbean islands have. It is not heavy in tourism. They have oil and gas, a major port. But as a constant outsider you spend a lot of time working out kind of what it is there for. To be in a place like that is really exciting to me still. Not exciting of the heart more exciting of the spirit. There is always inner reshaping going on…”

A detail from Chris Ofili’s original watercolour for The Caged Bird’s Song. Photograph: © Chris Ofili/courtesy the artist and Victoria Miro, London

He finds the perspective, the sense of being of the place but a bit removed, liberating, not only in his relation to Trinidad but also to the UK. “I love Manchester,” he says, “I love Manchester United. But I would really struggle to be creative there. I feel a bit lost, over-familiar maybe. Maybe too stuck in my own web of history…”

Ofili is telling me this story in the upstairs room of the Dovecot Studios in Edinburgh, where a different kind of web weaving has been going on. He is here for the unveiling of a huge tapestry of one of his watercolours that has been two and a half years in the making. The work has been commissioned from Ofili and Dovecot – one of only two working tapestry studios in the country – by the Clothworkers’ Company, one of London’s guilds, to hang permanently on the west wall of their dining hall.

When he was first approached by the Clothworkers in 2013, Ofili was intrigued but not convinced. “The idea of a commission felt a bit of a dead end,” he says now. “Like being caged in to do someone else’s idea.” When he politely declined, he was told that actually he could do whatever he wanted and that he didn’t even have to meet the guild members (“which was good because I felt I would carry some of their vibes into the piece”). And there was also the opportunity to work with the weavers at Dovecot, which traces a thread of its lineage making fine-art tapestry all the way back to William Morris.

Ofili had lately enjoyed returning home for a couple of other collaborations – one with the National Gallery, where he had been invited to respond to two new Titian acquisitions based on Ovid’s Greek myths. And the other with the Royal Ballet, where he had developed that response to Titian and Ovid into a living artwork in which he created a set based on his Trinidadian landscapes and painted directly on to the dancer’s bodies during the performance. He really liked the contrast that collaboration gave with his quite solitary work habits, and he saw the tapestry as another opportunity to explore that, a “kind of calling” from back home, he says. He made a small watercolour of an imagined scene of island life, and five weavers have spent something like 7,000 hours bringing it to life thread by thread. Today is the day that the final threads will be cut, and the tapestry, produced on a roll on a huge loom 18ft across, will be seen in its entirety for the first time.

‘I was interested to see if you could weave water’: Chris Ofili. Photograph: Kibwe Braithwaite/The Observer

Downstairs from where we are talking the great unveiling is being planned. The Company of Clothworkers, incorporated in 1528, are here in force along with curators from the National Gallery where the tapestry will hang before delivery to the guild over the summer. The moment is to be captured too by a BBC television crew, led by Alan Yentob, who has been making an Imagine documentary about Ofili. The crew had been out filming previously in Port of Spain, but Ofili had not been there to see them. He is wary of exposure, and sceptical of the fascination with artists beyond their work (his wife describes him as the “world’s most private man”) but he is, too, full of genuine anticipation over the culmination of what has been a long labour of love.

“It has been quite extraordinary working with the weavers,” he says. “For them it is really a two-and-a-half-year meditation. Sometimes I have come up here and it is clear this is not just about producing an artwork. They have to lose themselves in the process, the tiny gestures that they are making and millions of decisions about colour…”

His work has always been labour-intensive, with its layers of pigment and collage, his habit of overpainting and his experiments with texture and material; in the tapestry makers he has found kindred spirits. “To spend two and a half years moving thread around when you can get an image on your iPhone in milliseconds speaks to a different idea of time,” he says. “It becomes a life choice. How many are you really going to make in a lifetime?”

We are surrounded in the upstairs gallery room by the sketches and roughs of the original watercolour, which was made in Trinidad, and which the weavers keep in sight through the warp of their loom. Looking at the sketches you see Ofili as a sort of magic realist, mixing myth and the everyday in the spirit of novelists like Gabriel García Márquez. The scene he created for the tapestry, The Caged Bird’s Song takes some specifics of Trinidadian life and weaves a myth from them: the title refers not only to the Maya Angelou memoir, but also to the practice among Trinidad’s men of capturing songbirds for competition, and carrying them as they go about their lives in Port of Spain, to accustom them to the noise of traffic and street life. In Ofili’s painting, one such man holds a caged bird, which is being fed with seeds from the native “crab-eye grass” said to make the birds sing more sweetly. On the far side of the painting a woman also carries the plant, and in the centre it seems the two of them come together on a beach, and beneath a waterfall. The waterfall draws inspiration from Habio Falls in inland Trinidad, where Ofili and his family go to swim, but also from another location – a favourite kayaking spot – where in the rainy season water cascades straight into the ocean.

In a typical Ofili touch, this flow of water is set in motion at the top of the painting by a sort of celestial cocktail waiter, who on close inspection is modelled on the former Manchester City and Liverpool footballer Mario Balotelli. What’s he doing here?

Ofili laughs. He included the footballer partly to locate the story in the present, he says. “But he was chosen pretty deliberately. I am interested in him as an African European. Someone who has been both persecuted and celebrated. Someone who is almost mythical as a character. Who sets fire to his house. Who wears a shirt saying ‘Why always me?’ An orphan on the continent. Quite tortured and mysterious.”

Ofili doesn’t want to explain his painting much more than that, but is happy, hoping for it to be read as a story or an allegory. It looks to me like both a kind of expression of his great love affair with his life in Trinidad, or like those William Blake reveries of Adam and Eve before the fall (with a bit of Match of the Day thrown in).

Partly Ofili created the scene as a technical challenge, he says. He was fascinated by how the serendipitous pigmentation and bleeding of the watercolour would work at scale in the tapestry. “I was interested to see if you could weave water.”

When he describes his island life – hiking in the hills, sleeping on the beach with the children in hammocks, jogging in the hour he leaves the studio in the late afternoon, the great thrill of the home that David Adjaye has created for his family, the ad hoc open air film club he runs with Peter Doig – it is hard not to think of it as a kind of paradise. I wonder if he ever fears that truism that great art comes from difficulty; that happiness is the least interesting of all human states?

He does, he says, but not for very long. He suggests that even in pure happiness there is always a sense of the moment passing, of loss, something that he trusts this latest painting, in which a storm brews on the horizon, captures in full force. “Also, where I live, it is not only about the kind of joie de vivre that painters might have found in the south of France, say,” he says. He hesitates to call it a dark side, “but there are certainly peaks and valleys to island life. There’s a lot of poverty; there is crime. Racism and ‘shadeism’ that is unique to there. A brand of humour and nonchalance that some might see as distasteful. An ability to let go of problems that feels quite unique to Trinidad, in part because the people have always been faced with them.” Again he likes that sense of trying to grasp those unfamiliar complexities.

Balotelli (Sweet Cocktail) 4, 2014 , Ofili’s original watercolour detail for the tapestry. Photograph: © Chris Ofili, courtesy the artist/Victoria Miro, London

I wonder how easy it has been for his wife, who as well as being a musician has degrees in biology and neuroscience, and who initially, by some accounts, wasn’t as persuaded of Trinidad’s euphoric qualities as her new husband. He grins. “I wouldn’t speak for her,” he says, “but I think she is happy.”

Ofili has made a lot of money from his work – his larger paintings sell for nearly half a million dollars. A major exhibition of his new work will open the brand new outpost of Victoria Miro’s gallery in Venice on 10 May. He has kept a studio and a house in Hackney, and the family come back in the summer, which the kids find increasingly strange and exciting.

He himself approaches Britain these days with much more of a stranger’s eye, not least because its politics look increasingly unfamiliar. “You sense the rise in confidence of the right both here and in the States,” he says. “You thought those arguments had been won. But they are back in the mainstream.”

He tends to think it’s healthy sometimes for reactionary views to be aired. “But I don’t think they should be aired for very long.” The attitudes sound too familiar from his growing up in the 70s and 80s, he suggests. “It just seems to be all about limiting rather than expanding. Maybe it has to go in cycles. You go from Barack Obama, a man I think history will view as a significant figure, and then you have the current president whose name I don’t like to use. Someone who is clearly inherently not very generous as a human being, and probably very destructive. You wonder how that happens?”

Does he think of himself as a broadly political artist?

“I wouldn’t say even that I’m a broadly political person,” he says. “But on occasion I have felt that I have no choice but to paint something with a strong moral stance. The paintings now at Tate Britain, No Woman No Cry and Blue Devils, they are my Eric Bristow-type attempts to hit the bullseye of things that were going on.”

I wonder if the sensibility that produced his Turner prize work, the complicated celebration of his paintings, the directed anger of the Stephen Lawrence piece, feels like emotion from another stage of life for him?

“The things that I covered there, they are not irrelevant to me now, of course not,” he says. “But they are not the things I feel I need to explore at the moment. Change is not indecision. It is where the work happens.”

A little later we go down and watch the tapestry being prepared to be laid out for the first time in its entirety on the floor of the studio. It is a poignant moment, not least for the weavers who have lived with it for all those hours, creating a centimetre or two on a good day. There is a speech by the director of the Dovecot Studio, David Weir: “Love is proved by the letting go,” he suggests – and to prove the point Ofili goes along the thousands of threads with the Master Clothworker and a large pair of scissors cutting the ties that bind the work to the loom. While the triptych of the tapestry is unrolled Ofili stands and chats with the weavers who have worked his magic in silk. And then we all gaze down on a sudden explosion of Caribbean possibility in the grainy Edinburgh afternoon, and at Mario Balotelli, one part Prospero, one part mixologist, bringing it all to light.

Chris Ofili: Weaving Magic is at the National Gallery, London WC2, 26 April‑28 August