One of the sharpest minds in pop tells Neil McCormick how she fell back in love with music and why cigarettes are sensuous

'I'll try not to kill you with secondary smoke," says Joni Mitchell, as she lights up at the table. The great Canadian singer-songwriter likes her cigarettes, and, at 63, nothing is likely to persuade her to stop smoking now.

"It's one of life's great pleasures," she says, mischievously revelling in political incorrectness as she exhales a small cloud through wide nostrils.

Mitchell's speaking voice is a little husky, and her singing voice has noticeably altered over the years, losing the high end and modulating into a sensuous alto, but she blames age rather than tobacco. "I have smoked since I was nine, so obviously it didn't affect my early work that much."

And then she diverts into a rambling reminiscence of childhood in the remote farming community of Saskatoon. "I would grab my tobacco and get on my bike, looking for a beautiful place, a grove of trees or a field, and go amongst the bushes and smoke and that always gave me a sense of well being."

It was just such a moment, combining her love of the natural world with a sense of earthly pleasure, that inspired her first musical composition in over ten years. Mitchell had retreated from Los Angeles to her isolated estate in north Vancouver (bought in 1969, in the first flush of fame).

"It's a beautiful place of great complexity and mood. It doesn't take very long to get my centre back when I go up there.

To simplify. Because cities are so complicated, and our business is so complicated, being a public person is difficult at any time, but especially this time when everything is vicious and distorted. They soundbite you down, try to trick you into being an asshole?&?which isn't that hard."

Mitchell talks fast in huge tranches, jumping between tangential points, as if she has too many ideas and too little time. With her fine wrinkles and silvery blonde hair, she exhibits the elegant poise of an old hippy sage, yet gets almost girlishly giddy as she speaks.

She talks excitedly about standing on a rock, the Pacific Ocean rolling towards her, seals on the kelp, a heron crossing the sky, smoke undoubtedly filling her lungs, when she felt "such a sense of gratitude for having this place to recharge my spirit." She walked to her house, sat at the piano and started to play.

Strangely, for someone celebrated as one of popular music's most profound lyricists, the first piece was an instrumental, entitled One Week Last Summer. "I had made all these rules for myself: I'm not writing social commentary, I'm not writing love songs.

I blocked myself. All I had written was one haiku in ten years." In her own mind, at least, Mitchell had quietly retired from the music business, "just slipped away. My life came down to being a granny and watching a lot of television.

If I live as long as my parents (both still going at 90), I could go 30 years smoking in front of Ted Turner." But, almost unbidden, the songs started coming, until it turned into quite a torrent of work.

Earlier this year, she collaborated with Canadian choreographer Jean Grande-Maitre on a ballet, The Fiddle And The Drum.

A prolific and much-admired painter ("music was firstly a hobby to make money to smoke at art school", she says), Mitchell has a new exhibition in New York of photographic triptychs, entitled Green Flag Song. And she has released her 20th studio album, Shine (on Hear Music, the Starbucks label).

It is her first collection of original songs since Taming The Tiger in 1998. The thing that links all of the pieces is a gale force political anger. "I spent the last couple of years pissed off," she laughs.

"I was mad at America, mad at the government, mad at the people for not doing something about it. They were going to be so quick to impeach Clinton for kinky sex but slow to do something about Bush and his Nazi stormtroopers. All that loss of freedom and everybody just kind of oblivious. It's dumb and it's dangerous."

While the ballet and art exhibition focus on war, the lyrics of Shine pick up from her '60s classic Big Yellow Taxi (included in a revamped version) on environmental concerns. "I wasn't interested in escapist entertainment when the planet's on red alert.

We're busy wasting our time on this fairy tale war when nobody's fighting for God's creation." Yet she confesses the lyrics surprised her. "They just flowed out in the studio. I kept saying to the engineer, 'You're not going to like this."

' I was very reluctant to be Cassandra, some kind of prophetic doom sayer. I certainly don't want to be an angry old artist. Besides, the angry artist is attractive in a male but in a female is a bitch."

Mitchell is proud of the complexity that sets her apart from most contemporaries. "Pop songs are one sustainable mood. But my songs, they're like little plays, you may have four or five emotional changes in the context of one lyric, you have to switch internal spirits."

Although sales have been modest since her early million-selling albums (notably Clouds, Ladies of the Canyon and Blue) she is arguably the greatest female singer-songwriter of popular music, and, frankly, you get the feeling she would argue this point herself.

Contemporary reviews were often critical of innovative albums later adjudged classics, such as Court and Spark, The Hissing of Summer Lawns and Hejira, but when she talks about such matters the language she uses is extreme: "They tried to kill me;" "They came after me with a vengeance." It can make her seem prickly and over-sensitive.

Yet she is aware of the trait, and explains it as a reaction to feeling "boxed in". "I haven't been a folk singer since 1965, but all they see is a girl with a guitar, so I'm a folk singer. You can't see something for what it is if you pigeonhole it. We're in the pigeonholing business. So this makes it very hard for me, it makes me think people are fools, then they think I'm arrogant."

She doesn't like to cite gender as an excuse ("I feel very much a woman, but so what, so what?") but nonetheless clearly regards it as a factor in how the music business has treated her. "In the beginning there were hardly any women, now there are a lot of them?&but they are all flashing!"

She is utterly scathing about the artistic phillistinism of male music executives. "The record business is run by people who don't have any imagination, or encourage it. They don't love music. They love golf and porno."

Her disenchantment with music was such that she did not play or listen to anything for several years. "I didn't even have a radio. There was no loss, I had gotten to hate music, I couldn't remember what I ever really liked about it."

Then in 2005, Mitchell was asked to contribute to Starbucks' "Artist Choice" compilation series, and took six months listening to everything that had ever moved her. "Starbucks kept calling up: 'Why you taking so long?

Everybody else made a list and took the cheque.' But this was one of those life-and-death matters. I thought if I can get this right and remember why I loved music so much, I might have another record in me."

Some of the warmth of Shine, particularly the vibrato sax arrangements, she ascribes to reconnecting with the swing music she loved as a child. It is an album of gentle power, with strength in depth, addressing the very real problems facing the world with the voice of a great musical poet.

"It's got heart, and we need heart," says Mitchell. It concludes with a musical interpretation of Rudyard Kipling's classic If. "It gives me optimism. It's a good grocery list, very difficult to live up to. The thing about this album is that you can't really change the world, the only thing you can do is work on yourself."

It almost goes without saying that Mitchell has taken the liberty of "improving" Kipling's words. She felt that as a soldier, Kipling's emphasis on endurance was overly macho, compounded by his concluding "you'll be a man, my son".

"To endure is important, but that's not how you inherit the earth. My experience tells me that the earth is innocence, with wonder and delight, which is renewable. I wanted to get the feminine principle into the poetry."

Lest you consider such tampering sacrilege, the Kipling estate agreed to her changes, which actually do result in a message that is somehow more timeless and universal. "It needed rewriting," she smiles, brooking no disagreement.

As for her own endurance, she is optimistic about the possibility of more music to come. "I have some pieces. It's up to the muse."