Someone once said that the English have satire instead of revolutions. And this issue of the NS will no doubt prove the point: a bunch of us subject the most privileged and powerful caste in our society to a lot of incisive mockery, but nothing will change.

Yes, I know, satire can be quite an effective weapon, and has no doubt contributed to the downfall of individual politicians. Yet despite many years of acerbic ridicule, the class system remains intact, with the fortunate minority that Grayson Perry calls “Default Man” – white, middle-class, middle-aged, heterosexual males – stubbornly holding on to its power and privilege.

Clearly, each of these advantages (ethnicity, class, age, sexual orientation and gender) contributes to the supremacy of this group, globally and in the UK, but as it is not possible to cover them all, I will focus on the advantage that arguably matters most in what George Orwell called “the most class-ridden country under the sun”. In this culture, if you are working class, even being male, white, straight and middle-aged confers limited benefits. The tribe in question – the silverback alpha males who monopolise the high-status, high-income, high-power roles – is really more upper middle than plain old middle class. We are talking about the privately educated, well-connected, elite “establishment” here, not the common-or-garden male members of the large majority who now define themselves as middle class.

It is hard to come up with a better name than Default Man for this tiny demographic. Of the existing jargon, “dominant minority” probably comes closest, but generally refers to a power elite of a different ethnicity from the majority. I toyed with “British Brahmin” (borrowed from the American “Boston Brahmin”, snooty East Coast Wasps), because the caste reference helps to convey that our class system is more rigid than we care to admit. For now, however, I’ll call this high-caste minority Modal Man, after the term “modal personality”, which some anthropologists have used to describe a set of traits that are regarded as both “normal” and “normative” (proper, correct, socially desirable) in a given culture. “Modal” is not perfectly accurate in this case, as despite Modal Man’s stranglehold on education, government and the mainstream media, many people do not regard him as a normative exemplar – in fact, they may refer to him as a “posh git” – even if they covet his wealth, status or power.

Trouble is, if they aspire to more success, comfort and security – even to a modest degree – the majority have to conform to Modal Man’s norms. The term “modal” is also defined as “relating to mode or form as opposed to substance”, which seems appropriate in this context. We may not like or admire Modal Man, but we are in effect obliged to adopt his “modes and forms” – his sartorial, linguistic and non-verbal tribal affiliation signals, his customs and rituals. And we must at least appear to share his values, his world-view, his mindset. In short, we must learn to use the “cultural grammar” of his tribe. We must acculturate, assimilate and do our best to become what he would call “PLU”, which stands for “People Like Us” (although he never spells this out).

PLU is the English elite’s secret name for their own upper-middle-class tribe – the name they use, sotto voce, only among themselves. And anthropologists always respectfully refer to the tribes we study by these self-identified “endonyms”; it is highly incorrect to use externally imposed “exonyms”, which are often derogatory. Funnily enough, tribal endonyms such as “PLU” are often rather insular and complacent – translating as “the people”, “the true people”, “the normal people”, “the original people”, and so on. So I’ll be a good little anthropologist and call this tribe by its own smugly self-satisfied endonym.

Among the PLU, a person who exhibits lower-class tastes or traits – or, indeed, anyone who lacks fluency in the cultural grammar of this tribe – may be described as “nice enough, but not really PLU”. Someone who displays all the correct tribal-affiliation signals is approvingly designated “very PLU”. If this culturally fluent person happens to be from an ethnic minority, of lower-class origin, openly gay, a foreigner, or otherwise clearly “other”, he or she may be described, in surprised tones, as “actually very PLU”. During the 2008 US presidential primaries, for example, I heard an upper-middle-class Englishman say: “The thing about this Obama chap is that he’s actually very PLU!”

To be fair, the code name PLU is used by the women of this tribe as well. And to be scrupulously fair, both males and females tend to use it with a touch of irony. Phrases such as “very PLU” and “not quite PLU” are almost invariably uttered with a little self-deprecating laugh, showing that the speaker is conscious of being snobby and elitist, and is mocking himself a bit for this. In public, the PLU are even more careful to hide any signs of snobbery, practising a form of hypocritical courtesy that I call “polite egalitarianism”. Of all social groups in this country, the PLU are the most likely to insist that class divisions no longer matter, or at least that they themselves have no stuffy class prejudices. Some PLU may even sincerely believe this: the PLU have a remarkable talent for self-deception.

But, prejudiced or not, the English (of all social groups) are fitted with a sort of social GPS or class radar that registers people’s position on the class map the minute they open their mouths to speak. We do not judge a person’s social class by economic indicators. Money may buy you power, but the wealthy, working-class, self-made businessman is not “posh”. True social mobility – that is, being accepted as PLU by the PLU, with all the advantages this brings – can only be achieved through the three Es: education, exogamy and elocution. And neither of the first two – educating yourself into a prestigious profession or marrying into a PLU family – is effective without the third. Even if you also dress in PLU tribal costume and demonstrate impeccably PLU tastes and habits, if your accent and vocabulary are not PLU, you are “not really PLU”. Of all the forms of cultural capital by which the English judge a person’s social class, linguistic capital is by far the most important.

Class consciousness is by no means the preserve of the PLU: a person with a posh accent and vocabulary will be instantly identified as “other” in working-class ­social circles, as many PLU politicians have discovered to their cost. But the PLU, who have the most to gain from exclusivity, have the most sensitive and finely tuned class radar: one word or even one phoneme out of place and you are “not really PLU”. You can painstakingly train yourself to speak the PLU dialect but you are bound to make the occasional tiny error. You may remember to avoid all the principal shibboleths: “Pardon?”, “toilet”, “settee”, “lounge”, “serviette”, “patio”, “Pleased to meet you” and so on. You may give your children PLU names such as Jamie and Saskia, not Darren and Chantelle. But one day you have a nano­second lapse and nearly call your evening meal “tea” instead of “dinner”, correcting yourself just in time, so that it comes out “t- dinner”. That one little stray phoneme can be enough to set the PLU’s class-radar ­systems bleeping and flashing.

The PLU may give you the benefit of the doubt over one small plebeian slip of this sort, but their impostor-detection program has been activated and is now on alert, scanning you for other non-PLU indicators. You turn up for an informal summer lunch at a gastropub, carefully dressed in standard PLU, middle-aged male summer costume – pale-blue shirt and string-coloured or pale-beige loose-fitting trousers. You’ve remembered to wear brown shoes and a brown belt with this, not black. You are accompanied by a suitably PLU dog (Labrador) with an old PLU name (Monty). But oh dear, your hosts’ class radar is bleeping again: your belt and shoes look too new and shiny; your wristwatch is too big and flashy; Monty’s collar has his name on it in inverted commas; you are sitting with your legs too far apart; you remembered not to hold your knife like a pen, but you turned your fork prongs-up to eat your peas, instead of squashing them on to its convex back in the approved PLU manner . . . And then you did the social-climber stutter again, referring to the meal as “d-lunch”. This second offence confirms suspicions: you are “not really PLU”.

This country is not and never will be a classless society. For a start, there is no such thing. Every known human culture has a social hierarchy – even where wealth is fairly evenly distributed, or where there is little material wealth to distribute in the first place, there is always a system of social status and some means of indicating one’s position in that system.

Even if, by some miracle, a classless society were possible, this would be the last nation in which one might expect such a thing to emerge. Orwell was right, and whether you define class in terms of economic, social or cultural capital, nothing much has changed since his time. We are no closer to economic equality: the gap between rich and poor is getting wider every day. Nor have we achieved anything like equality of opportunity: social mobility has remained static, at best, since the 1970s.

All that has been achieved is an illusion of social mobility. About 70 per cent of us now call ourselves “middle class”, including 55 per cent of those in what market researchers define as C2DE (manual work) occupations. In fact, given a choice, 23 per cent of these skilled and unskilled manual workers even reject the modest “lower-middle” category, opting for “middle”.

Until very recently, it was the other way round: most of us defined ourselves (correctly, and often proudly) as working class, including a large percentage of those in what are classified as middle-class occupations. This discrepancy caused much puzzled debate among those who believe that occupation is a reliable guide to social class. I used to get calls from journalists asking me why all these ABC1s (professionals) were insisting on calling themselves working class. Now they are asking why all these C2DEs are calling themselves middle class.

Clearly, this identity shift partly reflects the expansion of many of the lowest-status jobs in the service sector – call centres are the new coal mines – which can be seen as “white collar” or “pink collar”; so those working in these occupations, however menial, undignified, precarious and poorly paid, can more easily define themselves as middle class. But more importantly, one can understand why they, and even those in the older “manual” occupations, would wish to do so, when successive PLU governments have promoted the relentless message that being working class is a problem, a condition from which one should aim to escape.

A young hairdresser summed this up for me recently, when she defined herself as “middle class” and I asked (intrigued, as she would be working class by any normal definition) what this meant to her. “That I’ve got some class, I suppose,” she replied. “Like, I dress nicely, I’ve got some ambition in life, I’m not just some lazy chav!”

I have had many similar responses in research interviews. A lot of low-paid, low-status workers have been fobbed off with the illusion that they are middle class. The PLU have pulled off a nifty little con-trick: rather than go to the effort and expense of paying such workers a decent wage or providing affordable housing, they have convinced people that “working class” is synonymous with “lazy chav”, and that they’re really middle class, just like their PLU rulers.

Yeah, right. Believe that, and you’re one short step from placidly accepting that “we’re all in this together”.

Kate Fox’s “Watching the English” is published by Hodder & Stoughton (£9.99)