I urge the people of Essex to stay indoors. A dangerous animal is on the loose: classism. In the past 48 hours, Britain has erupted in a paroxysm of sneering snobbishness. With the news that a lion might have been roaming the outermost fields of Clacton, a much wilder beast showed its face: the acceptable hatred of the (apparently) moneyed working class.

And so, Twitter has seen "lion" and "Essexlion" become its most discussed topics, as the incident is used to deride the people of this county. Essexism, it seems, is the last unchallenged prejudice.

First, countless supposedly hilarious pictures of the lion emerged: big cats with Photoshop-ed bouffant hairdos, because, of course, everyone in Essex has ridiculous hair. They have ridiculous hair, so the notion goes, because the men and women of Essex have no taste. They simply have money. And for the middle and upper classes, that will never be enough. Only "old" money ushers you into the upper echelons. However much a working-class person has "made good" – and that's a phrase that exposes the belief that the higher the strata, the greater the virtue – they will never be accepted.

And then there ensued a torrent of feline-themed Essex jokes. One of the more followed journalists on Twitter, who calls herself FleetStreetFox, and who has a column in the Daily Mirror Online – which, of course, has a substantial working-class readership – wrote: "#Essexlion will be several shades darker than most lions, French manicured claws and a taste for WKD." Thus, she niftily encapsulates three stereotypes in one: fake tan, fake nails and the "wrong" kind of dipsomania – one that is fuelled by cheap booze. The 18th-century outrage over proles binging on gin is alive and well.

Even The Observer columnist and broadcaster Lauren Laverne, who is from Sunderland, itself an oft-derided area for similar reasons, poked the escaped animal with a snob stick: "Hope they manage to find the Essex lion before somebody persuades it to get mane extensions and a vajazzle." Here she is making reference to The Only Way Is Essex, the television reality show which serves as a cornerstone for Essexism, by cherry-picking the most extreme embodiments of the county's female stereotypes.

How accurate are these representations? Does Helen Mirren fit the stereotype? Does Simon Amstell? Did Dudley Moore? Or, for that matter, my mother, who was born in Ilford yet somehow managed to become a lecturer and local councillor without ever having a manicure or spray tan? (Not that there's anything wrong with these things.)

There is no moral difference between laughing at people simply because of where they were born and mocking people because of the amount of melanin in their skin, their chromosomal makeup or their inability to walk.

And I should know. I'm from Guildford.