There will be no rewrite of "Candle in the Wind" for Jade Goody's funeral, but in her own glottal, gobby way, she jabbed a knitting needle into the subconscious of Britain just as surely as Diana Spencer did, and revealed something dark and darkening about us. Why was a big-hearted, big-mouthed young woman who came fourth on a reality show back in 2002 seized on with such glee and turned into one of the most famous people in the country? Because we needed her, to salve our own soiled consciences.

In her short life, Jade showed how as Britain has spiralled into one of the most unequal and immobile societies on earth, we have begun to openly jeer and sneer at the people trapped at the bottom. We gleefully seized on her as "proof" that the people rotting on abandoned estates were not there because of the grim accident of birth, but because they were stupid and ugly and bigoted. And all we proved – with unwitting irony – was our own stupidity and ugliness and bigotry.

Here was a 20-year-old girl with a noisy laugh, a quick wit, and almost no knowledge. She thought "East Angular" was a separate country, and wondered what currency they use in Liverpool. So the press jeered that she was "a moron", "the High Priestess of the Slagocracy", and "proof of Britain's underclass".

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That summer, a string of images of white, working-class women presenting them as bestial imbeciles dominated our screens. Vicky Pollard – a single mum so thick she swaps her baby for a Westlife CD, played by a multimillionaire private schoolboy – was becoming a national icon. A chaotic single mum established Wife Swap as one of our favourite shows. Words of straightforward snobbish abuse – "chav" and "pikey" – were becoming acceptable again.

Go to any extremely unequal society, say, South Africa, or South America, and you will find a furiously suppressed sense of guilt. It's hard not to ask, at the back of your mind, "Why am I here in this mansion, while they are in the slums?" This guilt is resolved one way: by convincing yourself that the poor are sub-human, and don't have feelings like you and me. Oh, the people in the barrios and townships? They're animals! They stink! They're stupid! Jade and Vicky and the labelling of the poor as "chavs" filled that role for us. They know nothing! They are repulsive!

Nobody wanted to stop and ask: why doesn't Jade know much? Here's why. Her mother was a seriously disabled drug addict, so Jade didn't go to school much because she stayed at home to look after her. From the age of five, she was in charge of doing the cooking and ironing and cleaning. Jade explained: "As early as I could remember, I'd spent my whole life trying to protect my mum, frantically hiding the stolen chequebooks she used to have lying around the house when the police barged in on one of their raids; desperately denying to the teachers at school that she'd hit me for fear of being sent to social services."

Her father treated her even worse. He stashed a gun under her cot, and her first memory was of him shooting heroin in her bedroom, his eyes rolling back and his body juddering. Eventually, after periods in and out of prison, he was found dead from an overdose in the toilet of a Kentucky Fried Chicken. "He died without a single vein left in his body," Jade said. "In the end, he'd injected every single part of it and all his veins had collapsed, even the ones in his penis."

Despite this, Jade always worked, in shops, for minimum wage, and stayed away from drugs (apart from weed). She applied for Big Brother because her mum was sinking into crack addiction, and she couldn't think of any other way to avoid witnessing it. To the end, she was terrified of matches, and couldn't bear to have tinfoil in her house, because they reminded her of crack.

And so she appeared in British public life, and we jeered and howled and held her up as a poster-girl for "the underclass". Jade soon proved her latent smartness by turning her fourth place on Big Brother into a fortune, launching her own brand of perfume, a beauty salon, and a series of sensitive, rather beautiful autobiographies, all appealing to young women who had never seen people just like themselves on television before. The perception of her slowly changed. As people learned about her life story – and saw her chaotic, broken mother being interviewed – many realised that their gleeful poring over her mispronunciations had been vile. The sense of superiority was, for a moment, scrambled.

Then came Celebrity Big Brother, and oh, how we rejoiced. Jade was placed in the house with Shilpa Shetty, a sweet, unworldly Bollywood star who had been raised with servants and never had to do anything practical for herself. She activated all of Jade's feelings of being sneered at and patronised all her life. Jade said: "Ultimately, we were fighting because we were from different classes ... I didn't want anyone to think they're better than me, just because they have more money or have had a more educated upbringing. And, to me, she was a posh, up-herself princess."

One day, Shilpa tried to flush an entire cooked chicken down the toilet. Jade, enraged and perplexed, started to scream at her. "Who the fuck are you? You aren't some Princess in Neverland!" she yelled. She said Shilpa clearly had no idea how ordinary Indians lived, and howled: "You need a day in the slums!" This was seized on as racist, equivalent to telling her to go back where she came from. But it wasn't. Other housemates did say despicable, racist things about Shilpa: the beauty queen Danielle Lloyd said "I think she should fuck off home ... She can't even speak English properly." But Jade didn't; her own father was mixed-race, for one.

But here was a way we could rehabilitate our Jaded view of the white working class, and feel self-righteous about it too. If we can't feel superior to the poor because they are stupid, then we can feel superior to them because they are racist. One newspaper ran the typical headline "Class vs Trash" over a picture of Shilpa and Jade, and a columnist huffed that Jade's problem was "hating her social superiors". Once more, we could hate the poor and feel good about it too.

And even when she was dying, we continued to jeer. Nobody said John Diamond was "exploiting" his cancer by writing about it in The Times, but Jade's decision to talk about it on TV so she could leave a pot of cash for her kids was apparently evidence of her "vulgarity". One newspaper huffs that now we will be subjected to "a chav state funeral".

Even as she rots, we still want to see Jade Goody as a "chav" imbecile, subconsciously reassuring us that our own higher place in the class pyramid is earned by our intellect and sensitivity and anti-racism, rather than by the fluke of birth.

Believe that if you want, but you should know it's not Jade you are condemning, but yourself.