Stoke Newington on the verge of derby weekend is not a place for the faint of heart. Located right in the centre of the bitter turf war between the ­historic rivals Arsenal and Tottenham, even on a sunny Friday lunchtime its leafy parks and terrace-lined streets drip with menace. Take a wrong turn, or catch the wrong eye, and nobody can really say what will happen next. A King Charles spaniel yowls ferally on the approach to Clissold Park. The blood on the pavement outside the bakery turns out, on closer inspection, to be jam from a doughnut. Such is the omertà around this 111-year feud, which resumes on Sunday afternoon at the Tottenham Hotspur Stadium, that local business owners feign impartiality or even ignorance of the forthcoming fixture, presumably wary of reprisals from rival fans. “Is it Spurs v Arsenal this weekend?” says a woman arranging the display of a local flower shop, who gives her name only as Laura. “I’m not much of a football fan.” Nobody in the local estate agent will claim an interest either, although one guy near the back – whose identity I have protected for his own safety – reckons Arsenal may struggle if they are without Martin Ødegaard. Undeterred, the Observer has embarked on a mission to discover what makes this derby one of the most ferociously contested grudge matches in the whole of professional sport. For the global television audience of ­millions, this is simply 90 minutes of product, along with all the attendant hype and gossip that accompanies it. But for those involved, it’s far more than that. It’s a way of life. Which is why this newspaper has decided to take a bold trek out of its comfort zone, into the oft-mythologised but largely uncharted wilderness known as “north London”. Who are these people? What drives and fulfils them? And how has football given back some pride to a region better known for centrist politics and open-water swimming? Three miles away, in the Coach & Horses pub on Tottenham High Road, the panel above the bar is bedecked in memorabilia, from signed shirts to flags. This is Spurs territory. A sign hooked around the whisky dispenser reads “Home Fans Only”. An Arsenal fan walking into this pub would quite literally be taking their life into their hands. It’s still only noon, but already a couple of hardened regulars have taken their usual seats at the back of the room. I ask, by way of conversational ice-breaker, whether they are Tottenham fans. “Sunderland,” replies one. “Shamrock Rovers,” says the bloke next to him in a Dublin accent, a wizened and genial old fellow who will later give his occupation as “male model”. “I’m the only Spurs in here,” calls the landlady, a jolly woman of middle years called Tina. As you can imagine, running a Spurs pub on derby day is not a job for the meek. The Coach & Horses will be packed to overfilling, security hired to keep order, as well as to enforce the rule on no visiting fans. But what about the rest of the time? What if an Arsenal fan – known pejoratively in these parts as a “Gooner” – were to stray over the threshold? Would they simply be turfed out? Or would a more exemplary punishment be demanded? “Oh, that rule’s just for match days,” Tina explains. “We get Arsenal fans in here all the time. There’s one over there. She’s my daughter.” She points towards the other end of the bar, where a young woman is chatting on her phone. It turns out that Tina is that rarest of specimens: a Tottenham sleeper cell. Her entire family are Arsenal fans. She even lives in Holloway, in the shadow of the Emirates Stadium. So how did she end up becoming baptised into the church of Tottenham? “Because I’m special,” she says. As with so many intractable conflicts, nobody quite knows where the battle lines lie. Hornsey and Finsbury Park are definitely Arsenal territory; Stamford Hill and Seven Sisters more Spurs. But even within these broad distinctions there is room for nuance. There are Spurs fans living in Holloway and Arsenal fans living in Walthamstow. Essex and Hertfordshire are contested territory. Rival tribes often live side by side, sharing the same workplaces and schools, even the same bed. The potential for skirmishes, even full-blown violence, is endless. Like many of the world’s other great derby cities – Glasgow, Rome, Buenos Aires, Belgrade – north London must feel like a tinder box constantly on the verge of ignition. “That’s religion, though, isn’t it?” posits an Arsenal fan in the Little Wonder cafe just off the Holloway Road. We’ve taken the short trip south, into Arsenal turf, in search of the opposite perspective on this eternal civil war. “This isn’t that. It’s just banter. Bragging rights. I mean, you always get a few idiots causing trouble. But we don’t hate each other.” “I don’t know about that,” his mate responds. “Tottenham fans are just different, aren’t they? Somehow. I can’t really explain it. Maybe it’s moral fibre.” Perhaps the deadliest flashpoint in the recent history of the Arsenal v Tottenham feud came almost a decade ago, when what should have been a joyous victory parade to mark Arsenal’s FA Cup triumph ended in ugly scenes. An Arsenal player called Jack Wilshere addressed the crowd outside the Emirates and started a familiar anti-Tottenham chant. “What do we think of Tottenham?” he asked. “Shit!” came the response. “What do we think of shit?” he continued. “Tottenham!” “Thank you!” he responded. In the pandemonium that followed, the club’s in-house TV channel was forced to cut its live feed of the parade. Wilshere was the subject of an internal disciplinary process and would leave the club barely a year later. Mark Doidge is a sociologist at Loughborough University and an expert in the culture of football fandom. “Football is a great way to understand how social groups form,” he says. “Who we are is partly about what we do in common with ­others like us. But it is also about who we are not. So rivalry is about bragging rights, symbolic superiority over ­others to reinforce who we are.” Why, then, do some rivalries inspire fear and carnage, while others feel so performative, almost forced, based exclusively in banter and irony? “It’s partly tied to cultures of masculinity and hooliganism,” Dr Doidge says. “Basically, the fans themselves bring emotion and intensity to the spectacle. “The more they care – the more their identity is wrapped up with the club in what psychologists call ‘fused identity’ – the more likely the rivalry will lead to off-the-pitch events. Maybe the context of north London provides other opportunities for fans to have identities away from football? Which means they are less likely to feel damaged by a loss?” The police vans and horses will be out in force again on Sunday, in anticipation of trouble. Broadcasters and social media accounts will remind us that this is a blood feud, a dynastic dispute almost as old as north London itself. Many of the fans descending on Tottenham from Islington and Stoke Newington, from Hackney and Heathrow airport, from the suburbs and the home counties, will have paid hundreds or even thousands to secure their place: a measure, perhaps, of just how deep the passion runs. Then a whistle will blow and the conflagration can begin: two tribes who thoroughly despise each other, or at least feel as if they probably should.