The chips are important. For aesthetic reasons, they must submerge the chicken entirely. The first rule of the chicken shop is that if you can see the chicken when you open the box, they haven’t given you enough chips. Too many chips, however, and you run the risk of filling yourself up before you’ve carved out enough space in the box to put the bones. This is where most people flout the second rule of the chicken shop, which is to start by eating some of the chips, proceed to the chicken, then – and only if required – eat the remaining chips, most of which will by now be lurking elusively in the box folds, turning the cardboard greasy and translucent.

These are my rules of the chicken shop, but yours may look radically different. After all, chicken shops are a little like countries: each operates by its own laws, and while you may feel comfortable visiting any of them, there will always be one you call home. Mine is the Brixton Road branch of the ubiquitous south London chain Morley’s. (London chicken shops are often fiercely territorial: you won’t find a Morley’s north of the river, a Pepe’s south of it, a Dixy Chicken west of the A1.) Each chicken shop has its own unique ambience and spice blend, its own cast of characters, its own policy on card payments (mine has a £3 minimum, others £5, a few still don’t accept them). And yet taken together, they constitute a cogent, deep-fried whole: as much a part of London working-class culture as the music hall and dog track were to previous generations.

“The chicken shop is London,” writes poet Bridget Minamore in Vice: for better or worse, to step into the humble high-street fried chicken joint is to breathe in something of the metropolis itself. Like much of the capital, chicken shops are built almost exclusively on the enterprise of first- and second-generation immigrants. They’re a staple of rap lyrics – “She can still roll Dixy chicken shop with me/She don’t care about no Hakkasan,” sings Not3s on the Steel Banglez track “Bad”. And in an age when public spaces are in decline, with those left suffering from social – and let’s face it, racial – cleansing, the chicken shop remains one of those rare places where all are welcome: noisy schoolchildren, teenage revellers, loved-up couples, minimum-wagers on the night shift, all united in the egalitarian promise of perhaps the last place on the high street where you can get a hearty (if not entirely healthy) meal for south of £3.

As one of the cradles of working-class, multi-ethnic London, Brixton has long had a thriving chicken shop scene. For decades there has been the big KFC on the corner of Coldharbour Lane, a Nando’s opposite the Brixton Academy for fancy dinners and date nights, two Morley’s, two branches of a flagrant Morley’s rip-off called MMM’s, a Chicken Cottage and at least a dozen more chicken and kebab spots of varying adequacy. Some have survived, some haven’t. And in recent years, as private investment has poured into Brixton, radically changing the aesthetic and demographic of the area, a new sort of chicken shop has entered the marketplace.

Several weeks ago, on Electric Avenue – the famous SW9 shopping street best known for its ethnic supermarkets, halal butchers and bustling market stalls – a restaurant called Bird opened.

Though it is new to Brixton, this is the sixth branch of Bird, an upmarket fried chicken chain that launched in Shoreditch in 2014. Bird’s stated mission is to do for the chicken shop what Byron did for the burger joint: reinvent it for a more affluent clientele. “The concept is to elevate fried chicken,” the company’s co-founder, a former investment banker called Paul Hemings, told the Evening Standard. “Which is on every block and every street, and has this image of schoolchildren eating out of a cardboard box on a street corner.”

You don’t have to try very hard to detect the subtext. In a way, Bird’s sniffy disdain towards its downmarket counterparts is merely one part of a broader front against the traditional chicken shop, which has become a sort of keyboard shortcut for degradation and high-street decay; perhaps even, with its high-calorie count and scant regard for animal welfare, an emblem of working-class fecklessness. Boris Johnson tried to crack down on them when he was mayor of London. More surprisingly, Sadiq Khan claimed there were too many when running for Johnson’s job in 2015. And you may recall the minor wave of outrage last year that followed the Home Office’s campaign to fight knife crime by issuing more than 300,000 specially branded chicken boxes bearing the government slogan #KnifeFree on the lid and “real-life stories” inside.

On the surface, it might seem that there is little to distinguish Bird from the rest of the shiny new middle-class food palaces popping up all over Brixton. The fancy noodle places and chichi cocktail bars are already hallmarks of the slow violence of gentrification. But given the cultural significance of the chicken shop, there’s something about Bird that feels particularly provocative: a flat rejection of London working-class culture in the place where it once thrived.

I thought I’d better try Bird before I rinsed it in print, so on a damp Monday afternoon I went in and ordered the chicken skillet (£12) with fries (£3.50). I ignored the extensive list of cocktails (Pornstar Spritz: £9), the lurid orange decor that gave the place the feel of a 1970s pub toilet, and the fact it was virtually empty apart from a table of hipsters with MacBooks. The chicken was well cooked but offensively spiced – it tasted like it hated me. Worst of all, it was still visible, even when you poured the chips over the top. In dim spirits, I left and set off around the corner in search of some proper chicken.