When I set out to write an account of England in the first decade or so of this century, I didn’t have comedian Roy Chubby Brown in my provisional cast list. But he forced his way in, demanding attention if only for being such an anomaly. He reached pensionable age in the dawn of the new millennium, a stubborn survival of a comic tradition that time forgot, but he was still selling out tour after tour, relishing his role as the alternative to alternative comedy, thriving in the margins of the mainstream. And his peculiar version of success seemed to say something about the times.

Coming on stage to an enthusiastic audience chant of “You fat bastard!”, Chubby Brown was a skittle-shaped, bespectacled figure wearing a garish patchworked suit, topped with 1930s flying helmet and goggles. He’d greet the audience – “Ey-oop, cunts!” – and then for the next ninety minutes he’d deliver an old-fashioned mix of one-liners, stories and songs. His material centred on sex, full of women who were up for it and women who were not, men who were frustrated or cuckolded or who had fantasies way out of their league; above all, it was rooted in his own grubbily implausible exploits and failures. Like the suit, the act was a vulgar, bastardised reminiscence of Max Miller half a century earlier, delivered with foul-mouthed glee.

He wasn’t welcome on television, but he built a sizeable audience with audio cassettes in the Eighties (Thick as Shit, Fucked If I Know, Kiss My Arse), and then with live videos and ultimately DVDs. They emerged every November and did very good festive business: in the run-up to Christmas 2009, his Too Fat to Be Gay was reported to be outselling Hello Wembley!, the latest Michael McIntyre release.

The two men could not have been further apart, in terms of style, appeal, even geography. As its title suggested, the BBC-approved McIntyre had recorded his DVD during his record-breaking six-night stint at the Wembley Arena, London; Brown’s was filmed at the Civic Hall, Wolverhampton. His heartlands were not London and the south-east; over the course of the Noughties he also filmed in Billingham, Birmingham (twice), Blackpool, Glasgow, Manchester, Newcastle upon Tyne, Northampton and Stoke-on-Trent.

His live audience was mostly male, almost exclusively white, rarely sober. They were considerably younger than him, and they were working class. “I entertain lorry drivers, road sweepers and people like that,” he said. “Fitters, welders.” You were more likely to encounter lagered-up lads on a stag weekend than students on a gap year.

Amid the filth, there were occasional dips into politics. “I was a Labour man all my life,” he reflected in an interview. “My father was a Labour man. We’re not posh people, we’re off council estates.” His response to the death of Margaret Thatcher in 2013 was to put ten minutes of abuse into his act: “Where I’m from, everybody hated her.”

He wasn’t New Labour, though. “So what has Iraqi freedom meant to you, then?” he challenged his audience. “Is your petrol cheaper? Does your lager taste better? Are you getting more pussy than you can handle?” Behind the typically earthy set of priorities, there lay a distinct lack of interest in “punching above our weight’”. And he was clear where he stood on Iraq. “Tony Blair should be hung,” he said in an interview. “He got us into a war that we should not have been involved in.”

And then there was the racist material, a minor but significant strand. Some of these gags were constructed in conventional fashion. “They’re fucking taking over,” he’d say (assuming we knew who “they” were); “before long, that fish shop’ll be called fucking Harry Ramadan’s.” Other bits, though, didn’t quite work as comedy. “I’m not saying that all Muslims are terrorists,” ran one line. “But isn’t it funny how all terrorists are fucking Muslims?” The rhythm is right, but the structure promises wordplay that doesn’t come. That was unusual. Brown wrote his own material and was a good technician — he had to be to achieve and sustain his level of success — yet when it came to immigration, he seemed to neglect his craft. And there were occasions when there was simply no joke at all, just frustration: “I don’t mind asylum seekers driving taxis, but I wish they’d learn to speak fucking English.”

That line got a massive roar from his audience. It wasn’t, though, a howl of hatred. Rather it resembled the dark delight of a football crowd cheering a particularly heavy tackle by a defender who was one of their own. He was the village idiot, licensed to say the unsayable on behalf of the serfs, to mock the morals that govern society, and ridicule the po-faced puritans who would police speech and culture. This stuff didn’t have to be crafted; simply the fact that it was uttered was sufficient. The audience reaction was the punchline.

Brown was, in effect, creating a bubble in which normal rules didn’t apply, a place where impure thoughts could be spoken aloud. But it was very definitely a comedy gig, not a political rally. The audience was not being incited by the clown onstage, not being wound up and charged to go out into the world. On the contrary, the roar sounded like a release of tension, so that the punters might return to normal life, having been purged. It was a comic catharsis.

It did, though, have a political element. Brown said in a 2007 interview that he’d noticed a change in how this material was being received. “When asylum seekers first started coming here I was talking about it on stage, but now that it’s in the news, when I talk about it people are on their feet applauding.” And he was clear that he meant what he said in his act: “behind every joke a comedian makes there’s a serious point”. The roar of approval was also the sound of the audience registering their acknowledgement of the serious point.

“I’m not a racist, or a sexist,” he protested, when those charges were laid against him; “I’m a humorist”. But the vocabulary alone — with its “poofters” and “cunts” — was enough to see him condemned. And increasingly he faced restrictions on where he could perform. Many of the medium-sized theatres in the country were owned by local councils, and there were some, particularly Labour administrations, who didn’t like the idea of him being on their property. He was banned at various times from civic venues in, among others, Ashfield, Bradford, Cambridge, Cardiff, Egremont, Hamilton, Ipswich, Leeds, Leicester, Llandudno, Oldham, even his home town of Middlesbrough.

Those bans enhanced his outsider status, but they were also a threat to his livelihood, and they left him bemused. “Compared to Jimmy Carr’s act, I’m like the archbishop of Canterbury,” he protested.

It was an intriguing comparison to invite. Because Carr’s material was based on a similar offence against politically correct politeness, with jokes about disability, homosexuals, paedophilia, the Holocaust, rape, domestic violence. The same could be said of Frankie Boyle. Each was creating a comfortably unsafe space where people could come together and listen to wicked thoughts that were forbidden in the real world. They were doing what comedians have always done: cheeking their betters, poking fun at public morality, pointing up the fallen nature of humanity and the frailties of the human body. And a huge part of the appeal was saying naughty things that jarred with the state-endorsed, non-judgemental celebration of diversity and inclusion.

There remained, though, a stubborn disparity between these comedians. However much outrage Carr and Boyle were said to provoke, it didn’t stop them appearing on television; indeed, they still present shows on mainstream channels. Brown, by contrast, was a broadcaster non grata throughout his career. There was little doubt who was the truly transgressive artist. But what precisely was his offence?

In Brown’s early days, the language he used was sufficient to keep him off the screen, but the standards of what was permissible had changed since then. In any event, he was intelligent enough to know that, like Carr and Boyle, he’d have to tone it down should he ever get the chance to appear on television. Nor was ribald material quite as frowned upon as once it had been.

In truth, it wasn’t vocabulary or subject matter that kept Brown off television, it was the fear that he meant what he said. As Ricky Gervais, another often controversial comic, explained, “You tell a sick joke with the express understanding that neither party is really like that.” It was doubted that Brown and — more importantly — his audience had that understanding, and the reason for the doubt was class. “Roy Chubby Brown is the most significant English male comedian of the past quarter-century,” wrote the academic Andy Medhurst; “he is a living, breathing, swearing, shocking (to some) reminder that class matters.” More specifically, Brown’s problem was one of education. He hadn’t been to university, and neither had his audience, so it was suspected that he and they were not properly schooled in modern manners.

Here was the great division in British comedy and, perhaps, in society more generally, a line drawn in the sand by tertiary education. From John Major onward, governments pursued a policy of increasing the number of students, and the gulf in society between those who had been to university and those who had not was becoming ever more apparent.

That gulf was cultural more than economic or even academic. In addition to their educational role, universities passed on orthodox values of liberal decency. In the context of comedy, a degree certificate was a licence to laugh at taboos, because it proved you knew why those taboos were important and could be trusted to place an ironic fig leaf over the offending areas. The subject of the degree mattered less than the fact it existed.

There was a potential danger here, of course. If taboo-breaking comedians did have a cathartic role, acting as a pressure valve to release feelings we knew we shouldn’t have and wished to vent safely, what were the consequences of denying this to half the country? Brown’s absence from television, combined with the council bans, made it look to his fans rather as though they themselves had been deemed unacceptable, too ill educated to be allowed access to their own culture. The fact that it was the same councils that had been responsible for their education merely added injury to insult.

Alwyn Turner’s All in It Together: England in the Early 21st Century is available now.