On the face of it, precious little has changed in the world of PJ Harvey in the 14 years since we first met. On that occasion, just ahead of the release of her second album, Rid of Me, the landlord in her local Dorset pub took me aside to explain that this shy, intense 23-year-old, whom he had known all her life, but whose music he had clearly never heard, was “the sweetest girl who ever walked the earth”.

Six more scarily magnificent albums later, the betting is that there’s a bit more to Polly Jean Harvey than that; but here we are again, sitting in the garden of another pub, a few miles nearer the sea, unravelling her latest collection, White Chalk. Back in 1993, she was living with her parents. Now home is a nearby clifftop on Dorset’s craggily picturesque Jurassic coast, in a place she moved into last year. But she can still jump into the Land Rover and be with her folks – her stonemason father and sculptress mother – in 20 minutes.

Fashions come and go, but, where her off-stage gear is concerned, Harvey remains a fan of the little black everything. Black is the natural colour of the first lady of British rock, an unsurprising choice given her long-standing fondness for writing songs with gothic titles, such as the first two tracks on White Chalk, The Devil and Dear Darkness. Are they, as many will suppose, more out-pourings of a troubled psyche? PJ continues to insist not, despite saying equivocal things such as “My work is my life”, or “I’m never really resting, just finding my way towards making my next record”. Which is hardly likely to discourage those who, she reports in a tone of tetchy bewilderment, “so often think my songs are autobiography, and they aren’t. My songs come from everywhere”.

As she will have discovered years ago, PJ Harvey-watchers tend not to dwell on the bright side. The fact that the only boyfriend she has ever been seen out and about with was Nick Cave – as close to a prince of darkness as rock stars got in 1995, when the two of them became a temporary item – seemed pretty clear evidence that domestic bliss of the conventional kind was not high on her agenda. There have been no reports of romance since, and many eagerly noted signs that Harvey might be a bride of misfortune. These have ranged from bouts of extreme skinniness, which spawned rumours that she suffers from an eating disorder, to the cosmically bad luck, bad timing, bad whatever, of her winning the Mercury music prize in 2001, for her album Songs from the City, Songs from the Sea. Who else but Harvey could have made such an upbeat – for her, anyway – record, partly inspired by New York, then been acclaimed for it on the very day, 9/11, when Manhattan turned into a killing field?

Today, however, we must park all of that. The fresh-faced, well-fed, 2007-model Harvey is a visibly happier woman than the one I met in 1993. And with good reason. The painfully reticent author of Rid of Me – an album of anguished guitar rock that screamed louder than any grunge band of the period, and moved Elvis Costello to remark that all her songs seemed to be about “blood and f***ing” – has blossomed into the serenely confident creator of White Chalk.

For once, the stock line recited by every rock star with a new album to sell – that this is their best one yet – rings true. While only Harvey could have made it, White Chalk sounds better, as in more original than anything she’s done before. It contains hardly any electric guitars and drums, no screaming or growling; and, though the lyrics contain references to traditional Harvey themes such as blood, death and insanity, the melodies are the sweetest she has ever written, which makes the overall tone anything but dark. From the delicate, bell-like textures of the mainly acoustic instruments to the gorgeous, not-quite-folky purity of Harvey’s vocals, White Chalk is a rock album of unusual, shimmering beauty.

“I’m really proud of it,” she announces, beaming. “This album is everything I wanted it to be, which doesn’t always happen. My goal is always not to repeat myself, but I’m a bit lenient on myself sometimes.” Quality control was on pause, she says, when she made her last album, 2004’s Uh Huh Her, which attracted the usual rave reviews, but sounded a bit like a résumé of Harvey’s previous work. “That record was just finding its way. I felt disappointed with it. I knew I had to be much more vigilant this time.”

As you might expect from a woman with such a singular approach, her vigilance took strange forms. The first thing Harvey did after concluding the Uh Huh Her tour in 2005 was to move to LA, where she owns a one-bedroom apartment. She spent the best part of a year there playing bass in a group run by Morris Tepper, formerly a member of the last incarnation of Captain Beefheart’s Magic Band. “It was fantastic. Lifting gear around, driving vans to venues, rehearsing and practising new songs. It really made me think about tuning in to other people, and I’m not used to doing that.”

Refreshed, she returned to the new house in Dorset and promptly ditched all thoughts of bands and bass guitars. Her new regime consisted of rising early and spending an hour at her blackboard with a piece of white chalk before trying to envisage a sound world to put around the words. Sometimes, it helped to draw pictures of certain songs.

After months spent loving playing the bass guitar, she was clear on one point. “I didn’t want anything bassy, or any drums. I wanted to create a sound with myriad melodies floating about, very unpinned down. I decided this record would live in the ether.” These sounds included old toy keyboards, Autoharps, zithers and nylon-stringed guitars, “mostly picked, not strummed”. The melodies were worked out on her new favourite instrument, the piano. “Such a huge great beast of a thing,” she notes approvingly. “And it can be played very violently.”

In the past, Harvey’s albums have, to varying degrees, possessed a tincture of the swamp blues she first heard at home, where her parents, mad blues fans both, liked to eat Sunday lunch to the strains of Captain Beef-heart’s Trout Mask Replica. While writing White Chalk, she listened exclusively to classical music. Her namesake and “great friend” Mick Harvey, the guitarist in Nick Cave’s Bad Seeds, sent her compilation tapes of music by Beethoven, Bach, Handel, Arvo Part, Gorecki and, her best new discovery, Vaughan Williams. “I find some of his work astonishingly beautiful. It freed me up from feeling tied down structurally.” There were no rules, she says, and “some very peculiar chord changes”.

After nearly a year of solitary monastic endeavour in her clifftop home, Harvey had written 50 songs. “I knew I had to write an enormous amount to find something that I hadn’t done before. I was very strict.” White Chalk took five months to record, longer than any of Harvey’s other albums. For most of last winter, she holed up in Kilburn, northwest London, in the home studio of her old producer buddy, Flood. To complement the new sounds, she decided she needed to sing differently, too. “I’ve never used this voice before. I call it my ‘church voice’, because it’s the one I would use when I went to church with my gran once a year to sing Christmas carols. I tried to sing like her, in a pure, unadorned, tuneful voice. I was focusing on not character-acting. I didn’t want to be, like, ‘Here’s my scary voice’, because that’s become a caricature.” It’s no coincidence, she thinks, that “all the children I’ve played this album to seem to really like it”.

Older fans won’t be disappointed by White Chalk’s tales of a brutally murdered wife (The Piano), the mother of a dead, or possibly aborted, child (the title track), and of a person turned mad by misfortune (The Devil). Many might be puzzled, though, as to why Harvey would choose to dwell on such grisly topics on an album she describes as “uplifting”.

Her answer says much about her intuitive obedience to an artistic credo she worships but barely understands – and one that most of her contemporaries are too busy playing celebrity catchup to bother with. “What can I do? I feel that the world is floating on darkness, and that’s what affects me most profoundly. It would be untruthful of me to sing la-di-dah songs about nothing. But I find that, in the music as a whole, that pain is offset by beauty and compassion.”

Harvey also finds that, ultimately, she has little control over how she and her music are perceived. And that makes her laugh. She was particularly tickled to discover that her duet with Thom Yorke, The Mess We’re In, had been used as part of a television programme about football. “Songs are like children. Beyond a certain point, they don’t wanna know you any more. They don’t even want to stand near you. This new record doesn’t really need me any more.” And with that, she grins and prepares to drive home. Alone, naturally.

PJ’s top 10

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1 Sheela-Na-Gig (1992) A very PJ sort of dirty love song about an ancient female fertility symbol.

2 Water (1992) A menacing exposition of grunge soft/loud dynamics – done, astonishingly, in 5/4 time.

3 Highway 61 Revisited (1993) Harvey at her fiercest, rocking out on a rare cover version.

4 Man-Size Sextet (1993) The PJ art-school experiment in full effect, complete with deranged strings and near-hysterical vocal.

5 To Bring You My Love (1995) Spooky swamp-blues, and an eloquent, womanly riposte to Zeppelin’s priapic overture Whole Lotta Love.

6 Down by the Water (1995) One of her first and finest murder ballads, underpinned by that unsettlingly perky latin beat.

7 A Perfect Day Elise (1998) A rich tapestry of distorted voices and warped rock grandiosity.

8 This Mess We’re In (2000) PJ’s one almost hit, a touchingly direct and hummable lament sung as a duet with Radiohead's Thom Yorke.

9 Crawl Home (2003) Loud and proud heavy rawk from PJ’s Desert Sessions, with Josh Homme of Queens of the Stone Age.

10 The Desperate Kingdom of Love (2004) A spine-chillingly quiet folk air for desolate voice and barely audible guitar.

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