What links these headline-making events of recent weeks: Emily Thornberry’s photo-tweet of a white van and St George’s cross in Rochester; David Mellor’s spat with a taxi driver; Andrew Mitchell’s defeat in his “plebgate” libel suit; the privately educated shadow education spokesman Tristram Hunt’s threat to lower the charity status of private schools; and the simultaneous screening last Monday of documentaries about the privileged milieu of Tatler magazine and the bleak existence of the unemployed in Grimsby?

The answer is social class. Like feminism and beards, class has made a dramatic comeback. Of course in any serious socioeconomic sense, it never went away. But it’s fair to say that for a couple of decades class went out of fashion, at least in politics.

The collapse of the Berlin Wall in 1989 buried the last vestiges of a Marxist analysis of class. The proletariat were not going to rise up. The revolution had been cancelled owing to a widespread lack of interest.

At home the divisive labour struggles of the Thatcher era had ended and in 1990 John Major announced plans to “make the whole of this country a genuinely classless society”. When New Labour came to power in 1997, Tony Blair confirmed the new paradigm by declaring that “the class war is over”. The talk was of combating “social exclusion” and increasing “social mobility”.

Mobility, with all its can-do dynamism, was presented as the remedy to the rigid fatalism of class. As politics converged on the centre ground, politicians from left and right competed in arguing who was best-positioned to deliver greater social mobility. The recurring message was that the nation was on the move, and it was moving up.

Now in the wake of the global economic crisis of 2008, recession and the slow, fragile recovery, an Oxford University report earlier this month announced that social mobility is still very much alive: it’s just that it’s now going mostly in the wrong direction.

The co-author of the report, Dr John Goldthorpe, said: “For the first time in a long time, we have got a generation coming through education and into the jobs market whose chances of social advancement are not better than their parents – they are worse.”

Goldthorpe is a dedicated empiricist with a formidable reputation for crunching data and an academic career stretching back half a century. He first made his mark in the early 1960s, when he discredited the theory, known as embourgeoisement, that the well-paid working class could assume the lifestyle and values of the middle class.

But he’s probably best known in sociological circles for the class schema he was instrumental in developing that enabled a more sophisticated analysis of social mobility. So when he talks of the “far-reaching political and wider social implications” of mostly downward mobility, he is not to be lightly dismissed.

One of the implications, he told the Observer last week, is that we can expect to see the return of a “more stable class structure”.

Since the second world war, there has been effectively unbroken growth in managerial and professional jobs. Not only has this rate of increase now slowed, there are also many more children from advantaged class backgrounds seeking work in the high-end sector. “We’re not going to have these very benign conditions of a rapid growth in top-end jobs, steadily promoting upward social mobility,” says Goldthorpe.

If that’s a concrete economic fact, then it’s a reasonable assumption that it will lead to increased status anxiety. In looking at social classification, sociologists make an important distinction between class and status.

“To put it very simply,” says Goldthorpe, “class relates to the way in which people make their living in the labour market, and status relates more to the way they then spend those earnings, their patterns of consumption and their lifestyle and social intimates.”

Over the last century we have seen a continual weakening in status distinctions and an obvious decline in such hierarchical social mechanisms as deference. But as Goldthorpe is quick to point out: “Several episodes in the last few weeks have shown that status issues are still there.”

Indeed they are. Perhaps nothing has illustrated that truth more effectively than the Labour MP Emily Thornberry’s tweet. On the surface, it was simply a photograph of a house and a van with a factual caption: “Image from #Rochester.” But in matters of class, especially in England, it’s what under the surface that really counts.

The St George’s cross and white van are symbols of a certain kind of England that is held in suspicion, if not contempt, by metropolitan opinion. To some, they evoke a belligerent nationalism and an aggressive maleness. There may be legitimate political or ideological reasons for this unease but it’s hard to disconnect them from a fear, or horror, of the white working class.

None of this was stated by Thornberry, but none of it had to be. It may have baffled foreigners, but most people in this country recognised why the tweet undid Ed Miliband, even if they may have disagreed with his on-the-spot sacking of Thornberry.

Whether she was conscious of it or not, she had implicitly asserted her superior social status, or to put it another way, denigrated the inferior status of a potential voter. Subsequently the photo has become a social media meme, adapted to reveal the complex interplay of class and politics in Britain. One reworking showed a hammer and sickle and a liveried Harrods van, as if to suggest caviar socialism was more to Thornberry’s taste.

“Status still matters,” says Goldthorpe. “The difference now is that when people who see themselves being of higher status adopt derogatory positions, there is a sharp response.”

But in the current climate, is the fear of that sharp response beginning to diminish? Certainly the Tory MP David Mellor did not appear overly inhibited by such concerns when he recently told a cab driver: “You’ve been driving a cab for 10 years, I’ve been in the cabinet, I’m an award-winning broadcaster, I’m a Queen’s counsel. You think that your experiences are anything compared to mine?”

That conversation was secretly recorded – unlike the disputed one at the centre of the libel case Andrew Mitchell has just lost. At issue there was whether or not he had called a policeman a “fucking pleb”. Although few us would feel confident about swearing at a policeman, that wasn’t the problem. It was the “pleb” that did for Mitchell.

Had he been accused of calling him an “fucking plod”, he’d probably still have a political career. Pleb is taboo because it refers to an unacceptable truth that is becoming ever more difficult to hide: we may be equal before the law, but not in terms of class. Seldom has this fact been more graphically exemplified than in last Monday night’s broadcast of Posh People: Inside Tatler on BBC2 and Skint on Channel 4. On the one hand we saw a group of elegantly dressed people living a charmed life of champagne parties in exclusive clubs and stately homes and on the other an underclass of the workless and the uneducated scraping an existence on benefits, crime and prostitution.

These two realities make a mockery of the notion that we’re living in a classless society. Yet at the same time it’s possible, and indeed quite likely, that most of us can go about our lives without having a direct encounter with either reality, but the fact that they exist undoubtedly adds to the growing sense of class friction and anxiety. They point to levels of privilege and deprivation that are hard to reconcile with any notion of progress towards a classless society. They also suggest separate and static social blocks – the one impenetrable; the other inescapable. In between them is an increasingly insecure middle class.

Goldthorpe identifies the parental panic over education as a likely sign of growing status anxiety. He cites, as examples, the premium on houses in areas with good state schools, the massive growth of private tutors and the assumption of false religious identities to access successful faith schools.

Such parents want their children to be able to compete with the products of the private schools sector – a sector that Tristram Hunt, Labour spokesman on education, says needs to do more for the community or risk losing its charitable status. Hunt’s argument has been dismissed, predictably, on the ground that he himself attended private school. Nowhere is the charge of hypocrisy more readily thrown about than in matters relating to class, and in particular class in the classroom.

Ultimately, all these parents want their children to enter a slowing high-end job sector. But it wasn’t supposed to be this way. The idea was that by radically expanding university education, a highly educated workforce would create its own demand. Goldthorpe says he took Gordon Brown to task over this flawed plan.

“I always thought it was a wildly optimistic view because we would have to compete with the new industrialising nations, who can produced highly qualified manpower and womanpower at much lower cost than we can.”

Now that it seems that the creation of graduates does not of itself generate demand for graduates, many prospective students are asking whether it makes sense to run up £30,000 or £40,000 debts at university. But, warns Goldthorpe, if tertiary-level qualifications no longer guarantee secure middle-class employment, “it’s not clear that not going to university is an altogether good option either”.

No wonder people feel as put upon as one of David Mellor’s cab drivers. All these stories of growing class anxiety suggest that in an age of economic uncertainty the social fault lines that prosperity had once concealed are now being exposed. And it is the centre of politics that consequently looks most unstable. Goldthorpe sees a historical irony in this development.

“Under the Blair-Gould project, you weren’t allowed to talk about social class. New Labour’s strategy was to focus on the median voter. It was pretty cynical in the sense that Labour’s traditional working-class supporter would have nowhere else to go. And the discovery now causing a good deal of alarm in Labour circles is that their traditional supporters do have somewhere else to go: Ukip.”

The return of class, says Goldthorpe, has not come clothed in old Marxist fashions. Instead he notes that both in Britain and in several other countries in Europe “it’s the growth of what one might call rightwing popularism that attracts significant working-class support”.

Which brings us back to Thornberry’s tweet. If it was an effort to convey the unsightly nature of this rightward trajectory, it was a symptom of what is hastening the drift. When it comes to matters of social status, condescension always lacks class.