What’s this on Maggi Hambling’s cluttered kitchen table? A Nicorette packet? Hambling, famed, louche sybarite, is always photographed with a fag in her hand. Horrified at my discovery, she shoos me upstairs to her immense double-height, double-width painting studio with its white floorboards splattered with black paint.

Hambling begs me not to reveal her secret but later relents, “now that I know you better”, revealing that she gave up smoking just before she turned 60 in October, “because my Dad did at 59 and he lived until 96”. But as a libertarian she hates “being told what to do. I’m completely pro-smoking,” and so will only be photographed with a cigarette.

She started when she was 14, “the hot summer’s day I first picked up oil paints. Insects were sticking to the palette. I asked my art teacher what to do and she said, ‘Have a cigarette’. Giving up was like losing a best friend. I didn’t think I’d be able to work again. I took to my bed for two weeks. I was miserable. I watched television. I drank. I don’t approve of giving up at all. Young people have years of wonderful smoking ahead of them.”

Hambling may be full of contrary bluster, but she doesn’t give up her secrets easily. She prowls her studio like a cat, falling quiet if she doesn’t like a question. She has a gravelly voice and a roguish glint in the eye.

Her first London exhibition in five years features paintings of the North Sea and some new portraits, embracing the celebrated (the Dalai Lama) and the unsung (a prostitute). She has a knack of fanning headlines — defending her controversial portrait of Michael Jackson, for example, or countering critics of Scallop, her stainless steel sculpture commemorating Benjamin Britten on Aldeburgh beach. It has just been defaced for a ninth time: “Tin can. Move it. Happy New Year.” Hambling sighs. “It’s such a waste of creative energy and a waste of public money to get the paint off.”

Hambling has been painting the sea in storm and repose for the past three years. She has a studio in Suffolk and was inspired by a storm raging across the water meadows. “The lashing waves seemed to be throwing the coast around.” These large oil paintings feature roiling, cresting waves and petrol-grey skies, occasionally broken by the red of a rising sun. At peace the sea is flecked with gold. People think of the North Sea as grey, she says, “but it’s full of colour”.

“I’m allergic to shellfish, which I think is quite funny given I spent two f****** years making a giant scallop,” she says, guffawing. “I also get seasick and I can’t swim.”

She rises at 5am in the summer, 6am in the winter. “The best energy happens early in the morning, before things have had a chance to go wrong. There’s no one beside the sea at that time. It’s corny, but tidal water is like life — always moving. When the wave breaks, it’s almost orgasmic. The rising sun is like a pair of lips.”

Hambling grew up in Suffolk. Her father was a banker. Her mother thought that she was “the most obstinate child she had ever come across. I was a tomboy. My brother, who had wanted a brother, ignored the fact I was a girl and taught me carpentry. I led gangs at school.” When the other schoolgirls were colouring in squares, she was drawing pictures of slaves being beaten, inspired by Uncle Tom’s Cabin. She became obsessed with Oscar Wilde. For her 12th birthday she asked for his complete works.

From a young age she “lusted” after women: at 4 she remembers a glamorous woman on the street “with false blonde curls, high heels, red lips and a black astrakhan coat”. She fancied her biology mistress. The female teachers, “wearing thick tweed suits and with odd tricorn hats”, would march up and down the lunch queue, shouting “No touching! No touching!”, which, says Hambling, laughing muckily, “encouraged one to touch everything possible”.

At 15 she started attending Benton End art school, run by Cedric Morris and his lover Arthur Lett-Haines. “They were total opposites. Cedric would be out at 5am collecting wild flowers, while Lett would appear at midday holding a dry martini.” She has long held dear the advice of Lett, who told her: “Make your work your best friend. Go to it whatever you are feeling.”

She left school halfway through her A levels, went to Ipswich School of Art, then Camberwell and the Slade. “To cover up the fact I was a virgin, which I was terribly embarrassed about, I wore a black leather coat, dyed my hair crimson and wore a fox fur. I looked like the madam of a brothel. The girls in the first year came to me for advice about contraception.” She made a list of the sexual possibilities that she wanted to explore: “A younger man, an older man, a black man, a woman. I worked my way through it and I liked the ladies best.”

Hambling’s debut exhibition in 1973 featured drinkers whom she encountered at The Cricketers, a Battersea pub where “drag queens mixed with dustmen”. In 1980 she became the first artist in residence at the National Gallery and achieved notoriety on the TV show Gallery wearing a fedora, drinking (“my glass was filled with vodka, not water”) and smoking.