Why I had to paint Rachel

Vine was seven when her parents split up and her mother, a seamstress, remarried the son of an RAF squadron leader. Vine didn't meet him until the day of their wedding and she says he took an instant dislike to her. Dominant and severely strict, her stepfather ruled their house in Norwich. "I was never part of the family," she says. "I was just an appendage they had to put up with."

When she was 13, she asked if she could go to a convent boarding school in Alnwick, Nor thumberland , where she was born. "It was a test," she says. "I'd had enough of being so left out and I wanted to see how much my mother wanted me. I was desperate for her to say 'No, don't go' but she didn't. She said it was a brilliant idea and that I would love it."

On the day her mother took her to the station to get the train north, Vine refused to say goodbye. " Looking back, I know she wanted the best for me. I know she wanted me to go away but only because she thought it was harmful for me to stay because I was having such a bad time. She used to say she wished she'd left me with my grandmother when she got married. I was heartbroken."

Rebellious and miserable at her new school, she only lasted a term, but when she returned home, the feeling that she was out of place was even stronger and she would stay out with friends all night, drinking in the local park. Her mother and stepfather suggested she go into a care home. Vine refused and instead moved in with a friend's mother. "She was a headmistress and enrolled me into another school," she says. "But I was bullied there, I didn't like being patronised by the teachers and I hated it so much."

She ran away when she was 14 and moved into a "dodgy bedsit" in Norwich, claiming she was 20, going to school occasionally and claiming benefits. The caretaker of the block took a liking to her and, despite being 10 years older, they began a relationship. She was 16 when she found out she was pregnant. "I desperately wanted the baby," she says, when I ask if she was scared. "I was more frightened of having an abortion. I wanted a baby I could love and who would love me. I thought it would be like having a kitten or a Tiny Tears doll I could dress up."

She broke up with the father of her child six months into the pregnancy and when her son, Jamie, was born, their relationship deteriorated even further. "I moved into a home for single-mothers and he broke in. He would follow me and try to snatch the baby in the street," she says. "One day I just left the house and didn't go back."

Instead, at 17, Vine came to London, followed her passion for acting by enrolling in the National Youth Theatre, and moved in with an Indian family in Tooting. "They were lovely," she says. "They baby-sat and let me join in their feasts but the house was infested with mice. I kept finding them under my pillow."

The young single mother and her baby moved around London for years, living in temporary accommodation before moving into a series of council flats. "It was awful," she says. "Really hard. It meant we never settled. We were homeless many times. I once suggested to my mother that I camp in her garden in a tent but my stepfather refused."

Poverty-stricken and sick of the meagre wages of jobs as an actress, waitress and cleaner, at the age of 26 Vine got a job as a stripper. "I was terrible at it in the beginning. I was unconfident about my body and would stand with my back against the wall scowling. Everyone said I had to smile if I wanted to make any money. I was usually drawn to the weirdos and the dirty old men. I found it easy to talk to them."

She worked in several clubs around London, making around £100 a night, and eventually got a job at the Windmill club in Soho, where she started to earn £400 a night. "The things that go through your mind are: don't fall over because you're wearing high heels, don't smudge your lipstick and don't get your bra caught in your hair. I didn't have much time to worry about cellulite or flabby bits."

Jamie, now 18, who makes hip-hop music in her basement, isn't exactly thrilled with his mum's career as a stripper but, says Vine: "He's streetwise, he knows about the real world and what I have to do to survive. We're proud of each other."

She can't say whether stripping has damaged her attitude to men or whether her inability to form healthy relationships comes from her relationship with her stepfather. Two years ago, she married Charles Thomson, a fiftysomething artist in New York. They had a huge row and she left that same day, her scruffy clothes thrown into a suitcase like the nomad she is.

She started painting four years ago, taking evening classes in life drawing at an art school, but it is Thomson, who co-founded the Stuckist movement (which believes only powerful, emotional paintings are true art), who takes the credit for Vine's raw, childlike style. Saatchi discovered her work when it was on show at another gallery last month and, thanks to the "Saatchi effect", she is now hoping to make a living as a fulltime artist.

Her darkest paintings started at around the time of her mother's death from cancer last summer. "That opened a big can of worms for me, stuff about my childhood that I had suppressed. My stepfather blamed me for her illness, saying all the stress I had put her under had given her cancer," she says tearfully.

Her paintings are clearly an expression of her troubled life but in reality, Vine is cheery and seems surprisingly well-adjusted. Ever the actress, it's hard to tell whether this is real or not. She doesn't, for instance, think stripping has left her with emotional scars but when I ask what the most dangerous situation she found herself in was, she won't say. "I'm not going there. There's some dark stuff that even I won't talk about," she says. There is the sense with Vine that her darkest work is yet to come.

New Blood opens at the Saatchi Gallery on 24 March.