To some Londoners, the North begins just outside M25, while in Cumbria, anywhere south of Blackpool reeks of the Midlands.
A 2017 study by the University of Sheffield, which asked people whether they saw themselves as southern or northern, settled on a dissatisfying diagonal line that placed Birmingham in the North, and Lincoln – 90 miles to its north-east – in the South.
While the question may seem unsolvable, if a new political movement gets its way we could soon get an answer to it.
The Northern Independence Party (NIP), founded late last year, campaigns to establish a progressive new state called Northumbria, and has already gained tens of thousands of online supporters.
Elliot Summerscales, the NIP’s press officer, joined the party in October last year soon after it was founded.
“I’ve always been quite fond of the idea of – at the very least – devolution for the North – some sort of northern Parliament or northern Assembly,” the 28-year-old says.
Like tens of thousands of the NIP’s followers online, the Leeds resident was first exposed to the party through its social media feed.
“My involvement started one day in October when I was on Twitter,” he explains. “They said they were democratic socialists and they were tweeting out very similar things to what I think.”
Over its short history, the party has accumulated more than 25,000 followers on social media, thanks in large part because the group knows how to attract an audience.
Its social media team fires off a mix of upbeat memes and – rather direct – criticisms of mainstream parties.
In a typical post, the NIP shared a photo of a gleaming futuristic cityscape with raised roadways and levitating cars, alongside the caption: “Sunderland – Year 2 of independence.”
And in another just this week, the NIP told Labour leader Sir Keir Starmer “don’t **** with Liverpool”, amid an ongoing row over Labour’s mayoral candidacy contest in the city.
Mr Summerscales claims this ability not to take itself too seriously on social media is one of the party’s strongest assets.
And despite its irreverent presentation online, the NIP is serious about independence.
“The end goal is an independent North – that's what we're after,” Mr Summerscales says.
“There is a widespread feeling that we are being left behind and that will only grow because the problems keep on getting worse.”
Last year, the results of a study that predated the coronavirus pandemic found that child poverty had surged towns and cities across the North of England.
The most striking increases were seen in Middlesbrough and Newcastle-upon-Tyne, where the proportion of children living in poverty now sits around 40 per cent.
The End Child Poverty campaign, which commissioned the report, said the alarming surge had been fuelled by stagnant household incomes and spiralling rents.
Nor is the inequality a recent development – average life expectancy in the North East has been lower than the rest of England for decades.
A plan to redraw UK constituency boundaries, ahead of the 2023 general election, is also almost certain to reduce the net number of seats in Wales, Scotland and the North of England – to the benefit of London and the Southeast.
“The South’s political influence only rises, while in the rest of the regions of the UK it diminishes,” says Mr Summerscales.
So where does a burgeoning campaign for northern independence look for inspiration?
“Naturally, you look to Scotland,” says Mr Summerscales.
For the NIP, the SNP represents what it could achieve in the North of England. And the focus on independence comes amid the backdrop in Wales, where the level of support for breaking away from the UK is similar to that which existed in Scotland a decade ago, but rising.
“The UK is inherently centralised in how it is structured,” he says. “And that's reflected in not just how the Conservatives think, but in how Labour think as well.
“Labour MPs in the North can’t hold the [UK] Government to account on issues facing the region because they’re part of a larger party.
“The party has to reflect the concerns of the entire UK all at once.”
He says the SNP has been rewarded electorally, time and again, because of its ability to focus on issues that affect Scots.
“People see how Westminster can actually be held to account by groups representing a specific region,” he says.
And Mr Summerscales has no doubt that Scottish nationalists will succeed.
“I think that seeing what happens with Scottish independence will definitely encourage it in other regions,” he says.
“It will probably be the first domino that falls that will lead to northern independence.”
Despite the optimism, Mr Summerscales is wary of the challenges facing the NIP and measures the march towards a new state of Northumbria in decades, not years.
“The SNP are the party of choice in Scotland, and are leaders of its secessionist movement, but it took them 40 years to get their first MP,” he says.
“And that was built on a strong Scottish national identity that already existed.”
One of the major challenges facing the NIP is to build an identity of its own.
“Scotland doesn’t have that trouble because it’s already a country in its own right,” he says.
“And while they're seeking independence from the UK, we are trying to establish a country from the ground up.”
So what about Northumbria’s southern border?
Officially, the NIP says its boundary lies on the south side of Cheshire and Yorkshire, allowing them to squeeze in the Peak District.
But for Mr Summerscales at least, drawing boundaries and dividing people up is not helpful.
“It’s not about where you were born, or where you live,” he says, “Anyone can be northern. The North is a state of mind.”