When I mentioned at a recent New Statesman editorial conference that I wanted to write about Kate Bush, who is preparing to release her first album for 12 years, colleagues responded with a mixture of incredulity and awe. The incredulous still associated her with a single song, “Wuthering Heights”, her first. Inspired by her teenage reading of Emily Bronte’s great and rather sinister novel about unfulfilled love, “Wuthering Heights” must be one of the strangest songs ever to reach number one, as it did in 1978. Nobody who has heard Bush’s wailing falsetto on that song, and its chorus of “Heathcliff, it’s me, Cathy/I’ve come home”, is likely to forget it. Nor is it any easier to forget her eccentric rendering of the song on Top of the Pops: with her thick, hennaed hair flowing wildly, as if she were running straight into a wind machine, she performed in a kind of rapture. Bush was 19 at the time and, a former student of dance and mime, desperately sincere.

The awed among my colleagues, who were all women, knew Bush for the complex and remarkable artist that she is, perhaps the most singular and talented female singer-songwriter and composer of her generation (she is now 46). There is no one quite like her. Without Kate Bush, there could have been no Madonna or Bjork, certainly in the guises—tough, independent, eccentric, committed, daring—that we know them.

Bush’s career began one afternoon in the mid-1970s when David Gilmour of Pink Floyd received a demo tape from a young girl. He liked what he heard, but thought the recording quality of the songs was poor. “The demo was not saleable,” Gilmour told me when we spoke. “The songs were too idiosyncratic: just Kate, this little schoolgirl who was maybe 15, singing away over a piano. You needed decent ears to hear the potential and I didn’t think there were many people with those working in record companies. But I was convinced from the beginning that this girl had remarkable talent.” Gilmour invited Bush to a recording studio and helped to record some more demos, which were produced by his friend Andrew Powell. They selected three songs, one of which was “The Man With the Child in His Eyes”, and took them to EMI. “They signed her up,” he says. She was on her way.

As an artist—and certainly as the interval between each new album lengthens exponentially—Bush occupies an ambiguous space between pop and the avant-garde, simultaneously working within and against the constraints of the pop song. She writes songs with choruses and tight, melodic structures while never abandoning her will to experiment: with form, with sampling technology, with unexpected instruments—a didgeridoo, uillean pipes, a mandolin—or with the texture and tone of her own voice, which can be at once a deep and disconcertingly powerful force and something far softer and more graceful.

As a songwriter, she can be opaque; her songs are often expressions of mood and feeling, often sexual feeling. She can write small, self-contained narratives, capsule stories such as “Babooshka” (about a husband who begins to receive seductive letters from an anonymous woman whom he discovers too late is his wife) or “Deeper Understanding” (about a lonely man who becomes addicted to his computer). She writes well about childhood and memory, but she can also be fey and hippyishly winsome: the titles alone of songs such as “The Big Sky”, “Wow” and “Big Stripey Lie” offer a flavour of her “hey, man” sensibility. She draws inspiration from Irish folk music, from literature (“The Sensual World”, with its ecstatic whispered cry of “Yes”, is based on Molly Bloom’s long, flowing soliloquy that ends Ulysses) and from film (the title track of The Red Shoes, not one of her best albums, was inspired by the Powell and Pressburger movie of the same name). And she sometimes even writes genuine protest songs—“Breathing” is about the nuclear threat, “Army Dreamers” is a fine anti-war song, and “Dreaming” is about the white settlers’ murderous exploitation of Aborigines and their land.

What has Kate Bush been doing since the release of The Red Shoes in 1993? What does she do when she is not working obsessively in the studio? What is she like? The mystery of Kate Bush is her essential unknowability—to outside observers, at least. Many years ago, she retreated into semi-reclusivity, reluctant to be interviewed or appear on television, never touring. There were rumours of her exhaustion and her hurt. Too much that was wounding had been written about her; she had been gossiped about and teased too much. For a period from the late Seventies to the early Eighties, there was scarcely a television comedian, from Kenny Everett to the foolish Eddie Large, who did not hesitate to ridicule Bush, especially her near-hysterical performance of “Wuthering Heights” on Top of the Pops.

I recall watching her being interviewed on BBC2’s Old Grey Whistle Test, one evening in 1985, I think, some time after the release of her best album, Hounds of Love. Her interviewers were sympathetic and evidently admired her, but it was still excruciating to watch as this then young, tentative woman, with her quiet, slightly lisping voice, who was so powerful and controlling in the studio yet so vulnerable away from it, submitted to a process that she clearly found intensely uncomfortable. It was increasingly clear that she wished only to speak through and be known by her work.

This was the beginning of her long period of withdrawal, during which she released only the disappointing Red Shoes. Her obsessive fans, the energetically self-styled Love-Hounds (log on to www.gaffa.org), became more and more restless for news about her. “I think creative control is so incredibly important,” she has said. “I’ve always been tenacious when it comes to my work and I became quickly aware of the outside pressures of being famous affecting my work. It seemed ironic that I was expected to do interviews and television which took me away from my work. It was no longer relevant that I wrote songs.”

Born in Kent in 1958, Kate Bush is the daughter of an English doctor father and an Irish mother. She grew up in a musical family: her mother sang, her father played piano and her elder brothers were both musicians (one of them, Paddy Bush, is among her most trusted collaborators). She began writing and recording songs as a young teenager, and by the time she met Gilmour she knew exactly what she wanted to do and how to do it. “When I first met Kate, she was this shy little schoolgirl, but very quickly you could see that she would have arguments with producers if they did not do things the way she wanted them to,” Gilmour recalls.

When her first single reached number one—much to the delighted surprise of EMI—Bush was liberated into privilege, and she has long had the kind of creative freedom to write and produce her own material that few recording artists are allowed. “Kate is a complete one-off,” Gilmour says. “I can’t think of anyone like her. Joni Mitchell was also a one-off, an original, but Kate is nothing like that. We need more people like her, especially as so much music amounts to little more than formulaic copying of genres. Those who have followed in her shadow are but pale imitations.”

Today Kate Bush lives with her partner, the musician Danny McIntosh, in what her friends like to call the “countryside”, but which is in fact a semi-rural location somewhere near Reading, where she has a home studio. She is a mother—her son, Bertie, was born in 1999—and, after many years of preparation, she is very close to completing her as yet untitled new album. But not even EMI knows exactly when or exactly what she will deliver. “It’s coming soon,” was all that I was told.

In a recent novel called Waiting for Kate Bush, John Mendelssohn wrote wittily about her mystery and allure—and of how that mystery has only been exacerbated as the wait for each new album has grown longer and longer. The wait is almost over.