At least five books have been published in France already this autumn on Michel Houellebecq, whose latest novel, The Possibility of an Island, was bought for £1m by the French house Editions Fayard. Academic conferences analysing the deep structures of his fiction as well as his political significance are being held all over Europe. Journalists everywhere delight in gossiping about his licentiousness and eccentricities - his smoking and drinking, and his fascination with religious sects and sex cults.

If interest in Houellebecq’s life and work remains inexorable, this is because, in many ways, the life is inextricable from the work. His central characters - his fatigued, sexually dissolute yet always yearning last men - share a vision of humanity slouching towards oblivion and address the world in the same sardonic, bored and scabrous voice. It is unmistakably the voice of Michel Houellebecq himself - but have we heard too much of it? Has he anything more to say beyond the programmatic recycling of the same preoccupations and effects? Is his comic nihilism, which once seemed so astonishingly authentic, beginning to resemble nothing more than a well-worked conceit, a mere party trick? The same trick, played over and over again, for considerable financial reward.

Every once alienated young man of a certain age can recall the abrupt opening to Albert Camus’s novel The Outsider: “Mother died today. Or maybe yesterday. I don’t know.” Houellebecq has evidently read Camus very carefully, and his hard-edged, confessional novels abound in comparable moments of existential isolation and wilful detachment. “On the day of my son’s suicide I made a tomato omelette. [. . .] I never loved that child: he was as stupid as his mother, and as nasty as his father. His death was far from a catastrophe; you can live without such human beings.”

The speaker here is a successful stand-up comedian called Daniel, the narrator of The Possibility of an Island. He is a recognisably Houellebecqian figure: middle-aged, jaded, death-preoccupied, sex-obsessed, sentimental if also cruel, misanthropic and very funny. Adrift in what he considers to be a terminally corrupt society, he delights in mocking the orthodoxies of the age, no matter what they are: liberalism, religious fundamentalism, consumerism. His comedy is a form of perpetual attack - against the world. He is, like his creator, a grand provocateur who seems to believe in nothing beyond the pursuit of intense erotic love.

Liberated from mundane concerns by his wealth, Daniel thinks he has found happiness when he meets Isabelle, the editor of a women’s style magazine. Together they go to live in the south of Spain, but they are both getting older, and Isabelle, horrified by what time is doing to her body, turns away from Daniel, no longer able to have sex with him. “When sexuality disappears,” Daniel writes, with searing insight, “it’s the body of the other that appears as a vaguely hostile presence; the sounds, movements and smells; even the presence of this body that you can no longer touch, nor sanctify through touch, becomes gradually oppressive.”

For a while, Daniel is lost, seeking out whores and embracing violence, until he becomes involved with a religious sect, the Elohimites, who practise free love (what else?) and whose leaders are experimenting with the possibility of cloning humans - this is a thinly disguised portrait of the Raelian cult, which claimed in 2002 to have created the first human clone, and among which Houellebecq has spent some time. One day Daniel meets a young actress called Esther. She is 22 and like many of her generation is, according to Daniel, interested only in pleasure, not in love. She is an enthusiastic, indulgent and complicit lover, even if she feels no love for Daniel. There is nothing the girl will not try and their sex scenes, as well as Esther’s hardcore adventures with other men, are described with the usual detailed relish. Daniel is tortured by jealousy. He wants to possess Esther but knows that, because of her extreme youth and carelessness, she will soon leave him, as she does, and that his body is decaying, that all around him is decay: “Well, yes, I was an ageing man, this was my disgrace - to borrow Coetzee’s term.”

He chooses suicide, as Isabelle has before him (why does Houellebecq condemn the women in his books to such bleak fates?), but not before he allows the Elohimites to take a sample of his DNA. And so Daniel lives on into the future, through a series of cloned replicants (Daniel2, Daniel3 . . . through to Daniel25). These cloned “neohumans”, inhabiting a post-apocalyptic landscape ravaged by global warming and nuclear war, comment retrospectively on Daniel’s sad struggles on earth, on the ruin of humanity and on their inability to understand abstractions such as love and happiness.

Houellebecq is fond of dreaming up a post-human future, as he did before in Atomised (1999), which was narrated by a clone. In truth, The Possibility of an Island is little more than a reworking of, or long appendage to, the earlier novel. The pre-occupations, the political sensibility, the expressions of ennui and drift, the wrenching longing, and the biting misanthropy, are the same. But Atomised was one of the most inspired and remarkable novels of the past 20 years, and this new offering, by contrast, reads more like a work of perspiration than of inspiration - and much of it is repetitive and tedious, especially the scenes among the Elohimites.

Towards the end, Daniel, separated from the two women he has loved, observes that “people become famous as a result of one or two talented productions, no more, it’s sufficiently surprising that a human being has one or two things to say, after that they manage their decline more or less peacefully, more or less painfully, that’s the way it goes.”

Houellebecq has one or two things to say and he is managing his own decline remarkably well - and profiting from it. But decline it is; Possibility is a less interesting book than Platform (2001), which was, in turn, a less interesting book than Atomised. You feel he has told his story. What one wants to read from him next, then, is not another novel, but a collection of aphorisms and gnomic utterances, a book of last things in the style of, say, the romantic French-Romanian nihilist E M Cioran. For one never ceases to be moved by the profound wisdom of his observations and the insight he offers into the complexities and corruptions of the present.