Before reading from his novel Mothering Sunday at the Edinburgh International Book Festival last weekend, Graham Swift warned his audience there were words and scenes of an adult nature in what was to follow. The eroticism of this exquisite book is as powerful as its language, although only one of the terms he used is controversial by today’s standards. He spoke it calmly, without sensation, but its impact was felt.

The c-word is the linguistic equivalent of propane gas: the lowest curse that can be hurled, the most pungent anatomical noun in the dictionary. Swift’s enthralled audience barely batted an eyelid, although one questioner seemed to have enjoyed working himself up into a mood of moral indignation, and a young woman texted me later to say she had been “shocked”.

That this ancient Norse word can still make headlines is instructive. Although it has been in documented use in Britain since the 1300s, it was not adopted as a term of abuse until centuries later, and only became nominally acceptable or even allowable in print in our own times. Perhaps that explains its continuing novelty value. Last week a judge who was insulted by a foul-mouthed defendant in the dock responded by saying he too was “a bit of a c***”. Told then to “f***-off”, she replied, “You too.” How could you not laugh and even cheer?

Yet it is not a word I can ever imagine uttering. The provocation would have to be exceptional. When I was a child even “struth” was a step too far, especially in a household where its blasphemous origins were taboo. But in future, perhaps, the epithet whose name shall not be spoken in polite circles will be as innocuous and invisible as that mildest of expressions now seems.

Swearing has always intrigued me, perhaps because it was forbidden. By the time I was old enough to say anything I liked, it was too late, like trying to spread cement when it has started to dry. Now, whenever I do lapse into Anglo-Saxon it feels wrong. It’s like wearing killer heels, or an arm inked with tattoos: just not me. Although, like most people, there are times when an oath escapes in the heat of the moment, usually when I’ve stubbed my toe. And apparently that’s alright. Studies have shown there is an analgesic effect in cursing. When volunteers’ hands were plunged into buckets of ice, those who found themselves effing and blinding managed their pain better than the buttoned-up.

Since neither Swift’s narrator, nor the judge was in physical pain, are their words justifiable or acceptable? In Swift’s case, indubitably. His usage was intended to be arresting, to draw attention to what language can do, which is what his novel is about. For Judge Patricia Lynch, it is less clear cut. Umbrage has been taken in stuffier legal quarters among those who fear either the dignity of the position has been eroded, or the role has been abused. To my mind she was taking the sting out of the defendant’s poisonous rage, thereby neutralising the nastiness of his tone and making him look as small as he deserved. However, whether she will be officially reprimanded remains to be seen.

Attitudes to uttering obscenities have changed so swiftly it’s no wonder people are confused. There was a time when one of the signifiers of being respectable was the way you spoke. Long before Tony Blair and his cronies turned the back room offices of the Labour Party bluer than a Tory rinse, foul language was becoming fashionable among the ruling classes, especially those from blue and white collar backgrounds. It was like having your cake and eating it: well-educated accents sugar-coating terms that started life in the criminal and social underworld and that would have made their mothers turn pale had they heard them. Meanwhile, in titled society swearing has always been a field sport, as competitive and unthinking an art as evicting tenants and bagging grouse. Some of the most proficient at expletives appear to think their elongated vowels make coarse words sound exotic. It is one of the upper classes' more endearing delusions. What they share with their vernacular peers, however, is their enthusiasm, and the hours of practice they put into this invigorating tongue. After a journey home on the No. 30, you can feel as if you’ve been through a verbal car wash, sprayed and lathered and wind-blown by a stream of overused, meaningless expletives from all around.

There’s no denying the habit is catching, just as there’s no doubt that in the right place, and the right time, there is no longer any shame or stigma attached. Be it in a publisher’s office, or a Michelin-starred kitchen, a pilot’s cockpit or a surgeon’s theatre, four-letter words are completely at home. In fact, I suspect more swearing goes on in the workplace than anywhere else, especially – but by no means exclusively – by men. Among executives and professionals it has become a signifier of energy and know-how, of the person showing he is in charge and in control. Depending on who is speaking and how, it can either be threatening, or no more disturbing – and occasionally as amusing – as an eight-year-old trying out dirty words.

In James Kelman’s Booker Prize winning novel How Late it Was, How Late, the point of Sammy’s cursing was not its coarseness, but its rhythm, the way the f-word had become as internalised as his heartbeat, almost as essential as breath. That some readers took the time to count how often it was used said more about their prejudices than their critical faculties. One of the best scenes in The Wire, according to Clive James, is where detectives McNulty and Bunk examine a crime scene and use only the f-word and its derivatives for a full five minutes while they unearth vital clues. It is a masterly piece of writing: the word is filled with meaning, from shock and disgust, to discovery and triumph. Not once is the tone disrespectful. Quite the reverse.

At times I wish I could speak this way. People like me are left looking twee or arch when, in testing circumstances, we search for the mot juste. The lexicon of epithets for the verbally inhibited seems to be drawn from the eras of P G Wodehouse and the late Moira Knox, who was annually outraged by goings-on at the Edinburgh Festival. It is completely unfit for purpose.

Nor should it only be kept for crises. There can be as much humour as catharsis or fighting spirit in an outburst of the obscene. As Alan Bennett discovered, some parts of Britain have a higher threshold for four-letter-words than others. In his forthcoming collection of diaries, the playwright notes of a tour of The History Boys in 2010 that when it begins in Plymouth, the c-word is greeted “in dead silence, but as the production slowly made its way north it got more and more of a response so by the time the play got to Glasgow they were throwing themselves about”.