Class is no longer banished from mainstream discussion, but it remains an uncomfortable topic for most mainstream media. The background to this is straightforward. The media all too often discriminate on the basis of parental wealth rather than talent: from unpaid internships to expensive postgraduate journalism qualifications, the routes into the industry are difficult to traverse without parents able to offer financial support. But most of us want to believe that our successes are personal achievements: that if we do well, it is because of our own ability, intelligence and determination. To realise that actually, you have queue-jumped, in effect, because of your parents’ bank balance: well, that would provoke insecurity and defensiveness. And so journalists and columnists are often disinclined to understand why society is stacked in the interests of some, but not others. Even raising the issue of class is felt as a personal attack.

That is one reason Lynsey Hanley is such a crucial voice. When she writes about class, she is writing about lived experience. Her new book, Respectable – the belated follow-up to her seminal Estates, published in 2007 – is a powerful investigation into the psychological impact, and cost, of shifting from class to class. She compares it to “emigrating from one side of the world, where you have to rescind your old passport, learn a new language and make gargantuan efforts if you are not to lose touch completely with the people and habits of your old life”. The case study? Hanley herself. The Personal Is Political would be as appropriate a subtitle for this book as any other.

Respectable compellingly (if sometimes erratically) weaves autobiography with academic research. Hanley grew up on a council estate in Chelmsley Wood, a 1960s ­new-build area of Solihull, in the West Midlands, a few miles from Birmingham. Her childhood, she says, would once have been labelled “respectable working class”: far removed from middle class but not “quite classically working class either” – rather, “foreman class” or “skilled tradesman class”. It feels wrong to infringe on Hanley’s right to self-define, but she does seem to have a very restrictive view of what being working class entails, so much so, that she isn’t entirely convinced she belongs. There has long been a clash between those who define class as a cultural identity and those who believe it has more to do with economic relationships (and those who think it is a combination of the two).

At Hanley’s school, “people didn’t do A-levels”. The high achievers ended up at the gas board or the Rover works and the word “university” evoked “something as distant as Mars”. Her school had 600 unfilled places, “effectively . . . abandoned by the community as much as by the local authority and by central government”. Hanley has always felt like an outsider: she struggled to make friends, found the limits of what was expected of someone from her background suffocating, and when – against the odds – she made it to sixth form, it seemed “one minute I was struggling for air, the next I felt as though I’d entered a large bubble of pure oxygen”. She looks to academics to help explain experiences she found difficult to navigate at the time. Her sense of isolation, for instance, can be illuminated by the sociologist Angela McRobbie’s exploration of “the ‘hermetically sealed’ nature of working-class culture in Birmingham”. The Uses of Literacy, Richard Hoggart’s 1957 classic, is her Bible; she feels he “could have been writing about my own childhood”.

Aged 17, Hanley was juggling five ­A-levels with four jobs: working at Greggs, selling Avon products, delivering newspapers and “making cakes and chocolates and selling them door to door”. But she became a professional journalist. When she was a teenager she visited Aldi to buy margarine and glacé cherries; now she comes back with “cold-pressed rapeseed oil and Pinot Noir”. She says “lunch” where she used to say “dinner”.

This is a well-crafted book full of insights. Hanley is determined to challenge the assumptions of left and right. She refers to socio-linguists such as Basil Bernstein, who examined how middle-class forms of communication were given preference over working-class expression but not because they were innately superior. Those who made the leap from working class to middle class found themselves assimilated by the new world. Many found it increasingly difficult to relate to the world they grew up in, and the people they grew up with.

Hanley thinks the approaches of both left and right to social mobility are problematic. Whereas the right uncritically worships the idea of “social mobility” – of parachuting the “lucky few” into the middle class without challenging the structure of society – the left, she says, believes that “social justice and social mobility are mutually exclusive”. In other words, she is questioning that old socialist maxim: “Rise with your class, not above it.”

Hanley assails those – including me – who place support for populist anti-immigration movements in a broader social context. She believes that we are downplaying the extent of racism in working-class communities, reducing it to fears over housing and jobs. We are robbing people of agency by letting individuals off the hook for their prejudices, she argues, stressing the casual racism she encountered on a daily basis. Disturbingly, she found that racism was often seen as a “sign of respectability”. She remembers sentiments along the lines of “Only common people hang out with darkies” and so on. My parents met through the Trotskyist movement; my father eventually became a white-collar local authority worker, my mother an IT lecturer at Salford University, and I was always by far the most middle-class of my friends. I’m not going to wish away the casual racism I encountered growing up in Stockport (and I’m white), but I’m not sure I’m entirely convinced by Hanley’s argument. Why is there an anti-immigration party with mass support now, yet there wasn’t one in the 1950s, when bigotry was far more open and widespread? Surely something has changed, and rising job, housing and general economic insecurity have had a role to play? And will a strategy of criticising people for voting Ukip – or even for the far right – win them over?

My main problem with Hanley’s book is this. Those of us who want to transform society so that it is not run as a racket for a tiny elite need to build a broad coalition. I’m a political activist who writes; Hanley is someone writing about reality as she has lived it. But her book surely challenges attempts to build unity between the working and middle classes. She writes of how middle-class people both hog and deny their “social and cultural capital”, and believes that those who argue in favour of a “99 Per Cent” under attack by an elite help entrench middle-class privilege. The middle classes pretend they have the same interests as the working class, while using their sharp elbows to keep them down.

I wonder if there is a third way. Abolish unpaid internships; introduce scholarships; invest in education at an early age; automatically enrol the brightest working-class young people into top universities; deal with social crises, such as the lack of affordable housing, which help destroy opportunity for the less privileged; have a proper living wage. And so on. But if those who believe in social justice fail to build a coalition of supermarket worker and schoolteacher, cleaner and junior doctor, factory worker and university lecturer . . . well, we will fail. From the low-paid against the unemployed, to private-sector against public-sector worker, to indigene against immigrant, there are enough divisions exploited by the powerful as it is.

Nonetheless, Respectable is of vital importance: a searing indictment of a chronically unjust society in which our opportunities are granted or denied from the earliest of ages. The book may not offer clear prescriptions, but it is incumbent on all of us to fight for a just and equal society – one that currently does not exist.

Owen Jones’s Chavs: the Demonisation of the Working Class is newly republished in paperback by Verso