According to British cultural critic Jonathan Meades, there exists an "Iron Curtain of Irony" in the United Kingdom that charts its course from Liverpool to just south of Grimsby. North of this division, he maintains, the idea of speaking against yourself — of saying the opposite of what you mean — is about as popular as Sydney Cooke. Of course, this statement is but another searing irony. What Meades is describing here (in form and substance) is one of the dominant modes of British humour; his delineation of an imaginary fault line in comic tastes used conversely to describe its shared nature through the deployment of the idiom itself — sarky British patter. Put bluntly, he's just taking the piss, folks, and in time-honoured fashion too.

And Meades makes a good point here, because this fictional division is no more real than the idea that there's a totality of what constitutes humour. We may indeed share certain sensibilities when it comes to having a laugh, but in sharing them such totality becomes impossible, since ownership is never total. This too follows the very trajectory of aural gags; of dirty jokes told by old men in public houses that everyone knows the punchlines to but concede to hearing anew nonetheless. Humour, like fiction, is a landscape wrought by the friction of familiarly imagined subjects and imaginary settings. It may seem plausible, for example, that the chicken crossed the road. But for what purpose? And ultimately, why the fuck is the conclusion funny at all? These things are never fully explained. Comedy therefore occupies a truly opaque space, where its object is revealed at the end but never quite reasoned. It's a territory where delivery and timing rule supreme, and a site that Momus (also known as the Scottish musician Nick Currie) explores in The Book of Jokes, until very little is left uncharted.

Or so it would seem. Confluence and ambiguity are all prevalent in this, Currie's second novel, narrated at turns by a paedophilic father called Sebastian Skeleton and his abused son, Peter. Here, the imaginary and the imagined conspire against the reader through its form, which is essentially a series of standard skits distorted into the original framework of a novel. This too, however becomes uncertain due to the similarity of the father and son's narrative purpose. On the one hand, the former is doomed to retrace his offence by agreeing to escape from prison with two men simply called the Molester and the Murderer, who form a glib pact to enact the crimes that they were incarcerated for, and so vindicate their original prison sentences, of which they believe themselves to be innocent. In the latter, Peter is condemned to recount his father's criminal perversion using jokes, which he explains away as some sort of grim psychiatrist's coping mechanism, based on the spiritual principle of Dharma.

But is that really the purpose of humour? This is the question Momus raises and his answers are stark; or rather, obscene. To take a leaf from the stand up comic's handbook, there exists an unwritten rule in the trade that jokes about kiddy fiddlers are out of bounds. Yet this is exactly what Momus is gunning for here, and social transgression couldn't be further from his game. What this book is satirising is this duplicity of, on the one hand, maintaining that by making light of the world's ills we are able to understand them and find them less terrible and, on the other, telling us that certain things can never be laughed at, no matter how unreal we make them.

But make no mistake — The Book of Jokes is not mere tatty pornography. Its target here is authority, not your own personal sense of decency. It is a piece of moral philosophising that takes aim at hypocrisy and fires at will with the deftness of Flann O'Brien's tongue and B.S. Johnson's imagination. In his 2005 documentary, Grizzly Man, Werner Herzog essentially suggested that the powerful should not avert their gaze, and Currie certainly does nothing of the sort here. If that upsets you, then you should probably avoid reading this tome and take to living underneath a rock.

What's more, it's impressive that after nearly three decades of languishing in relative obscurity, Momus — an artist once better known for aping Brel, Bowie and Gainsbourg — has come to the forefront and written not just one of the most entertaining books of the last twelve months, but two; the other being The Book of Scotlands. Funny, then, that the only publishers interested in printing his work are American. And to think, we all thought the Yanks didn't understand sarcasm — more fool us.

The Book of Jokes by Momus is published by Dalkey Archive Press and is available now