At my primary and secondary schools in the 1980s and early 90s, we were all working class. We lived together on a peripheral estate outside Birmingham; our parents did routine jobs or were out of work; and, at 16, we were pretty much all expected to leave or go “to the tech” to do childcare or mechanics. These experiences and assumptions were not that different whether we were white, black or brown, because the fact of being working class in a working-class area gave us a sense that our destinies were largely shared.

Twenty-five years later, my old schools and area are characterised as “white working class”, even though around 10% of the local population come from ethnic minorities. More recently, politicians on both sides of the Atlantic have seized on the demographic of the “white working class” to explain Britain’s vote for Brexit and the rise of Trump. But since when did the “white working class” become a separate group from the working class in general? Who decided that “they” were so different that they needed their own club, their own set of dog-whistles and coded encouragements to victimhood?

On Tuesday, the Runnymede Trust and the Centre for Labour and Social Studies thinktanks produced a new essay collection, Minority Report, seeking to debunk the power of the term and end its divisive use. Its editors, Omar Khan and Faiza Shaheen, comment with elegant understatement that since the EU referendum campaign “debates on race and class have descended from inadequate to toxic”.

Along with “multiculturalism has failed”, one of the preoccupations of politicians and commentators for the past decade has been trying to define and meet the needs of “the white working class” at the same time as turning working-class people – assumed to be white, as though being black or Asian automatically disqualifies you from membership of a social class – into unknowable curios.

The contributors to the Runnymede report express alarm that the Brexit vote has given legitimacy to a desire among political leaders on the right – supported and enabled by the rightwing press – to divide shared class interests into competing racial groups. The problem is that the term “white working class” has come to be used across the political spectrum for differing reasons, but with similar effects.

Some on the right use “white working class” to pit people in similar circumstances against each other. Some on the left, meanwhile, are suspicious of what they regard as a malevolent New Labour project to ignore white working-class people in favour of those from ethnic minorities, out of a combination of guilt, exoticism and an erroneous belief in the universality of “white privilege”.

Here, the “white working class” becomes “the left behind”: those perceived to be uniformly bewildered by change, whose sense of loss began in the era of mass immigration and not hundreds of years before, in the time of land enclosures, rapid industrialisation and continual migration and violence. Elements of the Conservative party and Ukip as a whole see vast political gains to be made from encouraging a sense of victimhood among people whose relative economic stability has been hard-won and, they perceive, short-lived. Whether or not they are right is another matter, given the inability of Ukip’s Paul Nuttall to win the Stoke-on-Trent Central byelection last month, and suggests that working-class people are not as daft as he had hoped.

The term first gained wider currency around 15 years ago, partly as a result New Labour’s failure to treat the narrowing of class divisions as a project more complex than chucking City money at former pit villages. In 2004, the author Michael Collins published The Likes of Us: A Biography of the White Working Class, which sought to paint the south London of his childhood as an unchanged, socially cohesive entity for centuries until immigration and multiculturalism were “imposed” on its residents from above.

The vogue is to describe working-class people as 'the left behind'

A few years later, the BBC chipped in with its own guilt-ridden intervention, the White Season, about the white working class. The term seemed to have become an insidious shorthand in media and political discourse for people the middle-class media landscape could not get a grip on: people who looked like them but who seemed to have an entirely different set of values that had been ignored and needed exposure.

The current vogue is to describe working class people as “left behind”, but all these terms mean similar things: people who are written about as if they are curious moon specimens, and are believed to hold the same views en masse and thus are not really responsible for their actions; people who are nostalgic, backward and need to get with the programme. This is all part of the current political story that says everyone is totally responsible for their own lives, except when they are racist – and even then they must have somehow been “driven to it” by all these nasty foreigners taking their jobs.

Owen Hatherley, author of The Ministry of Nostalgia, reckons “the idea of the working class as a ‘forgotten tribe’ is a way of depoliticising class, and making class into another interest group. [It’s treated as] a sort of nationality, based on accent, culture and a particular set of views. Among other things this makes it possible to see self-employed small businessmen who own houses in the south-east as working class, when in any economic definition they’re petit bourgeois.”

In its 13 years in power, Labour hoped that, with enough redistribution to former industrial regions – often by creating public sector jobs in areas of low private-sector growth – and by repeating “we’re all middle class now” often enough, class would wither away without the necessity to confront directly the way that the disadvantages of being working class are embedded in the overarching structure of society.

The National Equality Panel, established by Harriet Harman a year and a half before Labour were voted out of government in 2010, sought to enshrine legislation to prevent employers from discriminating against job applicants and employees on the grounds of social class, but was one of the first casualties of the coalition government.

As Labour belatedly turned its attention to class inequality, the British National Party began making gains in council seats in parts of northern England and on the peripheries of cities such as Leicester and London. Its leader, Nick Griffin, became an MEP for the north-west in 2009, holding on to his seat until 2014. Again, Labour MPs in mostly northern working-class seats perceived the BNP’s rise as symptomatic of the party’s move away from its “northern heartlands” (another soon-to-be wellworn cliche) and towards its other electoral constituencies in more glamorous places.

Yet, as Gargi Bhattacharyya points out in one of the Runnymede essays, a fixed idea of respectable “white working class” values – socially conservative and focused on the maintenance of law and order – was not only handy, but necessary for Labour ministers such as David Blunkett and Hazel Blears to carry out many of their more regressive domestic policies. Blunkett, in particular, seemed to take pleasure in the harshness of his stint as home secretary, going tough on crime (and quietly ditching his “tough on the causes of crime” mantra) as he instigated asbos and built new prisons.

Labour hoped that repeating 'We're all middle class now' would make class wither away

With fixed ideas come fixed identities, whether or not they bear any resemblance to the messy reality. The idea that immigration and multiculturalism has been “imposed” on an oddly static, inert and, by assumption, all-white working class doesn’t bear comparison with the reality. In areas such as Collins’s south London, working-class people moved in and out, and instigated mass migrations of their own to outer suburbs decades before widespread immigration from the Caribbean and south Asia.

My paternal grandfather was born in Ireland, my maternal grandmother in the South Wales valleys. Both came to Birmingham to work in factories; their children, my parents, are Brummies, as am I. They were white, and working class, yet also migrants – and in the case of my Irish granddad, one who in 1950s Birmingham didn’t count as “white” enough to fit in (he ended up returning to Dublin).

I asked Sathnam Sanghera, whose 2008 book The Boy With the Topknot brilliantly portrays working-class life in 80s Wolverhampton, how he feels about the term. “A context which implies [working-class people] are by definition white is annoying,” he says. “The working-class area I grew up in was white and black and Sikh – almost all my uncles and aunts were working in factories. Even now the Sikh community in Britain is only beginning to be lower middle class, and they seem to have backed Brexit, at least in Wolverhampton. The picture is much more complex than these easy black and white terms imply.”

The sociologist Paul Gilroy, whose influential book There Ain’t No Black in the Union Jack was published 30 years ago, noted in 2008 that British arguments about class, race and identity involved “the obsessive repetition of key themes – invasion, war, contamination, loss of identity – and the resulting mixture suggests that an anxious, melancholic mood has become part of the cultural infrastructure of the place”.

The use of the same stock terms point to the same questions: who belongs in Britain? Who is allowed to belong, and why does it change according to who you ask? Why is the messy reality of daily experience – people rubbing along, finding a way to co-exist, and, mysteriously for the likes of Nigel Farage, consistently refusing to erupt in race riots every 10 minutes – overlooked in favour of the easier story of Us and Them?

• Lynsey Hanley’s Respectable: Crossing the Class Divide is published by Penguin.