Billy Childish is a man of many words. During our interview, the 51 year old talks for almost three hours on everything from Jackson Pollock (“phony”), Martin Amis (“I hate him”) to Tibetan Buddhism (“very sensible,” apparently). It’s unsurprising that he has a lot to talk about. Childish is a fiercely prolific multi-hyphenate producer of art, music, poetry, prose, biography, and press. He was Tracey Emin’s ex-boyfriend, his name emblazoned across the inside of her infamous tent, Everyone I Have Ever Slept With 1963–1995. He had a spat with Jack White, who accused Childish of plagiarism. Childish replied: “I have a better moustache and a fully developed sense of humour.” He terrified punters outside the Tate Britain during Martin Creed’s Work No. 850 (which featured people running through the gallery) by turning up in a bright yellow suit and a sandwich board that said “SON OF ART”. Little wonder Channel 4 approached him to appear on Celebrity Big Brother (he said no).

You have to admire the man, if only for his panache. And yes, he does have an impressive moustache: it spreads expansively across his upper lip like an enormous, furry Cupid’s bow. Paired with Victorian braces and a badge that proclaims him to be a “Hero of the Brit Art Resistance”, he is every inch the idiosyncratic artist. Yet despite his charmingly dysfunctional relationship with the public and inexhaustible creative spark (resulting in about a hundred albums, 40 books of poetry, four novels, and thousands of paintings), it is likely that you’ve never heard of him. He’s remained an underground folk hero, his music praised by the likes of PJ Harvey, and Jack White (at least, pre-spat). He’s been dismissed as a “Bayswater-Road style dauber”, but is enjoying a revival with a retrospective at the ICA. His poetry has been more immediately recognised, having been twice commended in the National Poetry Prize, and his writing has seen him described as the “better-looking British Bukowski”. This is an ex-alcoholic who was routinely bullied as a child, sexually abused at age nine (him on the subject of his childhood: “I was bullied, I was emotionally and sexually abused, but apart from that I was happy”). He didn’t know how to read until he was 14, and was accepted under the ‘genius’ clause at Saint Martin’s School of Art, and then summarily expelled for publishing obscene poetry (“they told me that my attitude was not conducive to getting a degree”).

“Being a polymath is viewed with great suspicion,” Childish says. “Coming from an uneducated background is considered very bad. It challenges the structure of how we do things; things are viewed as whether that person has the permission to do that. [Art schools] are actually finishing schools. Particular students are chosen to be polished up… and exhibited if they’re obedient enough to represent their generation as an artist.”

Speaking of artists of the generation, what does he think of the YBAs? “I think there’s plenty of room [for the YBAs], I just don’t think it’s remarkable.” He solicitously avoids speaking ill of Emin, whom he met while she was at fashion college, though he does say this: “She did fashion, then she did art, she gave up art, and then went back into fashion. Called Brit Art.”

You’d think that there is plenty of room for him to be bitter: Hirst and his ilk have been raking in millions with their Swarovski-encrusted icy social commentary, while Childish remains comparatively uncelebrated. He helped found a relatively less successful art movement, the Stuckists, who were pointedly anti-conceptual art. He still lives in Chatham, Kent, where he grew up. His studio, where I meet him, hasn’t moved for the past decade or so: it remains on the second floor of his mother’s Whitstable house. And yet Childish seems to be unconcerned with success, and claims to be producing the art that he wants to see. “If art is done in a knowingly cocksure, ironic way,” Childish muses, “it’s considered clever. If it’s done with genuine feeling, it’s considered embarrassing and naïve.

“The good thing about art is that it can free you from delusion. In our society, we use art to compound it.” He warms to the subject, his moustache twitching. “Art is about a hunger for reality, rather than the collective delusion our society is obsessed with. Television. Celebrity. Bad food. Bad writing. Bad music. Everything that is pretending to be something. Our artists and musicians are complicit, so any talent or benefit they have,” he gestures grandly, “is wanked into the pocket of death.” He explodes into laughter.

This is what you get with Childish: you’re never quite sure when he’s taking the piss. His eyes twinkle, his moustache quivers with a grin. He’s a bag of barely suppressed feelings, at once incredibly arch and then explosively emotional. At one point, his mother comes in to offer us pizza. We’re on the topic of love. Once she exits, he leans in and immediately informs me that his mother did not love him, and that she was “not someone who has experienced love”. When she comes back into the room, he inquires with an almost excruciating amount of concern, if she’s eaten any of the pizza herself. You have no doubt that he means both sentiments – the concern and the pain behind the loveless childhood – but that he is compulsively unable to not be honest, and tempers that compulsion with an aggressive blend of trickster charm, a raised eyebrow that would challenge you to accept him as he is, were he already not so indifferent to what you think.

You see this emotional honesty in his work, too. His poetry and prose is deliberately uncensored, his haywire spelling (Childish has severe dyslexia) left untouched. His rock music, a blend of gutsy blues and garage, is as lo-fi as it gets: forget overproduction, there is barely any production at all. His mainly autobiographical, raw paintings are recklessly expressive; he doesn’t paint so much as attack the canvas. It’s not that he doesn’t know how – in his studio, I spot an early self-portrait from when he was 17 years old. It’s more immediately palatable than his current work, as if he’s trying to impress somebody with his obvious talent. He’s now spent his entire life working against that instinct. “You jam the cork in, and some things are squirming around – what you’re trying to do is loosen the cork. I don’t think things are learnt. They’re present, just obscured. You need to find ways to let it out.”

Later on in the interview, he grows philosophical. “A tree might have been a dinosaur tooth, and it’s all space dust.” Things are simultaneously everything else they can be? He turns to me, eyes twinkling with that peculiar brand of Puck-ish liveliness. “These are games of understanding. I always get into trouble because I talk in big generalisations. I say, so how the fuck else are you supposed to discuss anything?”

Painter, poet, musician – they’re all the same, he implies. Childish is everything he is: a mass of contradictions rubbing up against each other in varying levels of harmony. And that’s just Billy for you: unashamedly, unapologetically, irresistibly Childish.