"BE PUNCTUAL," they implored. "Be punctual, and everything should be all right." Ask about Nina Simone at her publisher's offices and you'll soon be appraised of the relationship between tardiness and the musician's volatile temper.

And you did your best. Honest. But between London and Manchester points failed, signals stuck, engineering work progressed and cattle strayed on to the tracks near Rugby. Meanwhile, the telephone wires between the Manchester hotel where Nina Simone is staying and Q Magazine's HQ have been glowing red. "Miss Simone," word has it, "is a trifle anxious".

"Shouldn't you have been here over an hour ago?" enquires the hotel receptionist – usually militantly neutral in such matters – as you skate across the lobby. It is now 90 minutes after the appointed time of your meeting with the fire-breathing legend. It can't get any worse. It does.

"Miss Simone," her manager tells you, breaking an icy silence as the lift ascends, is now "a little tense."

IN THE SUITE, Miss Simone looks every inch the slighted diva and the old tales of how she'd sternly dress down audiences before storming off stage become horribly vivid. The atmosphere is not so much frosty as Siberian (on a really cold day).

"Do you know much about me?" she demands, her rich voice dripping with disdain.

"Er, enough to know that I shouldn't have been late." Silence. Then an unexpected and rather wonderful sound. Miss Simone has thrown back her head and is roaring with laughter.

Instant thaw. Coats are taken, seats offered, fags flashed and champagne uncorked. For somebody who has prompted widespread use of such adjectives as "illogical" and, less charitably, "barking", it transpires that Nina Simone can, in fact, be friendly, humorous and lucid. Indeed, the only apparent anomaly is her choice of cigarette – called Naturels, she maintains they're good for her throat, but light one up and they're instantly recognisable as a foreign relative of those old tonsil-tearers, Capstan Full Strength. Furthermore (contrary to her publisher's dire warnings) she's entirely happy to explain why there's so little mention of music in her newly-released autobiography – a book appropriately titled I Put A Spell On You.

"OF COURSE the book doesn't talk much about my music," she smiles patiently, pouring the champagne. "The book is the story of my life and I am only part musician. A lot of men have been in my life, I've been through a lot of situations."

Some might argue that since her music is the very reason she's able to get an autobiography published, a degree of insight into three decades of unique writing and recording ought to be in there, somewhere – alongside the disastrous relationships, global wanderings and flirtations with politics and politicians (including a long-running affair with a Prime Minister of Barbados). And yet, once the book gets far past its subject's teens, save for moving accounts of the backgrounds to her songs 'Mississippi Goddam' and 'To Be Young, Gifted And Black', the main clues as to Nina Simone's job description are a few references to albums (usually in the context of monies owed) and details of exhausting, frequently mismanaged tour schedules.

"Because that's exactly what music is to me – a job. The popular music I became well known for never inspired me at all, because it was all so simple. It was nothing compared with the classical music I had been studying for 25 years before I even made a record, and I disrespected it completely for a very long time. All you had to do was create a mood and the people would be right there with you. It was so easy. I only began changing my outlook towards popular music when I started making money at it, and then it wasn't the music itself I took seriously but what went with it. I had to work almost as hard as I had when I studied classical, doing press, doing television, organising touring itineraries and remembering a repertoire of up to 500 songs. It was a job that I wanted to do well. I still dream about playing classical concerts though, but that won't happen now because I don't practice enough."

To call Nina Simone a reluctant recording star would be an understatement. On recording her first album, Little Girl Blue (featuring 'I Loves You Porgy' and 'My Baby Just Cares For Me') in 1957, she was so certain that she was "a classical pianist, not some pop star" that she paid no attention to the contract she signed and now she reckons this casual action has cost her upwards of a million dollars. But at the time she had her reasons. Since the age of six, when Eunice Waymon was two years into piano lessons, she burned with ambition to become America's first black classical pianist – a post she believes is still vacant 50 years later. Thanks to the proud towns-people's generosity (an ongoing whip-round called The Eunice Waymon Fund) she attended a boarding school for the musically gifted at 11 and six years later, in 1951, attended the Julliard College in New York for 12 months' preparation to take the scholarship exam to Philadephia's prestigious Curtis Institute. Despite her obvious ability, her enrolment was not to be.

"The Curtis Institute refused to consider my scholarship application because I was black. I knew I was much better than many of the students who had passed it. That rejection left me hurt and bitter for many years, because although I was aware of the racial divisions from growing up in the South, up until then the white people I'd come into contact with through my music – at home and in the schools – had always been very supportive. Going to the Curtis Institute was something I'd practised for six hours every day and I don't think I've ever quite recovered from that disappointment."

That particular setback served to turn Eunice Waymon into Nina Simone. As the Fund had deep but not bottomless pockets, this meant finding regular work. It came in the form of playing accompaniment to a local singing teacher, then performing in bars in Atlantic City. Playing seven 45-minute sets per night, for "an audience of drunken bums", to keep boredom at bay she evolved the quasi-classical style that was to make her famous. Starting from the popular songs she was expected to play, she improvised around their basic themes, weaving in ideas from classics, blues and hymns. It was not unusual for numbers to last 30 minutes. Unsurprisingly, Nina Simone began attracting her own audience – largely students working in the resort for the summer, the advance guard of the beat generation – and as her reputation grew, so did record company interest.

Simultaneously, as the Civil Rights movement began stirring in the '60s, Nina Simone – prompted by the Curtis Institute incident – embraced it with few reservations.

"By that time I was well known, but although I was earning money and making a career of it, deep down I still didn't care for the music I was making. With the Civil Rights movement, though, I saw that by singing protest songs and appearing on platforms for the various organisations I could use my interpretations of popular music to speak out to and for black people all over the world. I was desperate to be accepted by the Civil Rights leaders and when I was, I gave them 10 years of singing protest songs. In turn, it was the only time when I've been truly inspired by anything other than the music of composers like Mozart, Czerny, Lizst and Rachmaninov."

Whether the protest movement was actually a source of inspiration or merely the ideal outlet for her deep sense of frustration (the hardest working emotion in I Put A Spell On You) is open to question. Simone admits to following the various factions "instinctively rather than intellectually", often feeling like an outsider as life in the celebrity fast lane kept her away from the barricades. Eventually, she admits, she lost faith in non-violent protest: "The Klan weren't non-violent, so why should we be?"

Meanwhile, her musical career continued to flourish. It was during this period that she wrote accepted classics such as 'To Be Young Gifted And Black', 'Mississippi Goddam', 'The King Of Love Is Dead' and 'Four Women', as well as recording her truly soulful interpretations of words by the radical poets Langston Hughes ('The Backlash Blues') and Paul Dunbar ('Compensation'), and scored a huge hit with 'Ain't Got No...I Got Life'. But like so much of her life, her time as a protest singer ended in personal dissatisfaction.

"It died after those 10 years," she sighs. "So many of the figureheads were either dead, in jail or had gone abroad and of those that were left, it was as if the movement wasn't fashionable any more. They just gave up and got respectable. I felt as if my people had just rolled over and played dead and I hated them for it. I was more than let down, I was the most disappointed person in the world and regretted the 10 years of my life I'd given them.

"What made it worse was I couldn't go back to what I'd done before because I was labelled a protest singer. Record companies either thought I'd be trouble or that nobody would be interested in me singing love songs. It was a stigma I couldn't get away from, as in Europe – one of my biggest markets – protest songs were all they knew me for and I had to go on singing them. That remains ironic, as they don't care about what those songs stood for – it wasn't something that affected them so they didn't need to find out about it. It's just nostalgia for a type of music and very difficult for me to get inspired when I perform them under those circumstances.

"I was also being investigated by the IRS who claimed I owed a fortune in taxes, when so often I hadn't even been paid the money concerned. So I left the USA. I ended up in Africa in 1974, where for nearly five years I made no music at all. I wanted nothing more to do with it because it seemed to have brought me nothing but heartache yet it had taken my whole life. From the age of four I'd been stuck in a room all day long by myself and what I'd missed all my life was a life. I was determined to make up for that. I wanted nothing more to do with the United States either, which is where you had to be if you were serious about recording. In fact, I wanted nothing more to do with the world outside of black Africa. I only started recording again in Switzerland in 1979 because I needed the money."

NOW – THANKS to a new-found control over her career and cashflow – much of Nina Simone's anger has receded: "I'm much more relaxed now. I live well in Amsterdam, I don't have a problem with money, I go out, I watch movies, I entertain, I go to health clubs, I eat, drink and make merry. I've settled with the IRS so I can go back to America when I want to. Really, I can put aside more time for myself as I don't have to perform so often and work so hard."

But this 1990s model is not without spirit, and recently she's found that spark of inspiration returning. It seems her contribution to contemporary black politics and music is only a phone call away.

"I haven't felt this positive about what is going on in the USA for a long time. I'm playing to more all-black audiences now than I ever have done and I'll perform the old songs for them in the way they were conceived, as I know they're being appreciated properly. I've never been an advocate of non-violence. I believe the only way to get anything is by any means necessary and that seems to be an attitude that's resurfacing today. People like Spike Lee, Louis Farrakhan, who I've known since the '60s (she once, tipsily, tried to seduce the devout Moslem), and certain rap artists are continuing the fight in the way it should have been carried on 20 years ago.

"I have a great respect for the rappers that are carrying a message to black youth, but I have no respect at all for rap as music. Because it isn't. It has no harmony, no melody, no written music and it's killing black music which has always been the most melodically inventive of forms. They should learn a bit more about their history and their music, and most could learn from old-timers like me. I'd be willing to go along and sing some of the old songs with them. All they have to do is ask..."

In spite of that benevolent offer and this afternoon's uncharacteristic display of new-found patience, it would be unwise to assume that Nina Simone's flame is anywhere near extinguished. She'll still refuse, she says, to be any less forgiving to audiences, black or white, who devote less than 100 per cent concentration to her performance.

"I don't do it as much as I used to," she shrugs. "Audiences know when they come to see me they have to listen, otherwise I'll curse them out. And when I'm cursing out an audience you better believe that I mean every word. I'll still do it now if I have to. I don't care."