AK Blakemore’s second novel is inspired by the real life story of Tarare, a showman in 18th-century France who made his living by demonstrating a prodigious ability to devour things: heaps of fruit, corks, stones, live animals, offal. Born to a peasant family, by his teens he was able to eat his own weight in meat in a day and was driven from home lest he ruin his parents. He became a street performer in Paris during the revolutionary period, and in the wars that followed he was a soldier and briefly a spy. This is clearly a tale that begs to be fictionalised, and it’s hard to think of a better writer to do it than Blakemore. Her debut, The Manningtree Witches, about the witch-hunts of 17th-century England, won the Desmond Elliott prize and was shortlisted for the Costa. It was lauded for the extravagant beauty of its language, full of wild wordplay and precise imagery, and her vision of the period felt both accurate and vividly new, in the manner of the greatest historical fiction. Blakemore and Tarare seem like an unbeatable combination. Indeed, The Glutton is remarkable for its beautiful language, for its hallucinatory imagery, and for its ability to mingle these things with the world of 18th-century poor folk. We believe absolutely in Blakemore’s smuggler who complains that “the peasant is taxed of his arse and taxed of his elbow by the ink-shitters of the customshouses”; in her rebellious peasant who says, “Until the fainting of the Wormwood star, there will always be more to kill.” We see clearly the prosperous farmhouse that is “not a fine house, but a good house, set back from the road in well-tended fields belonging all to itself, lights shining yellow in the windows”. Many details are a complex mix of tenderness and revulsion, such as the dead rat whose “fingers are clutched at its own downy breast, frozen in an attitude of strangely human-seeming panic” before Tarare devours it. Blakemore clearly knows the revolutionary period, and sees it from an unexpected angle; the ideas stand as the recreational bullshit of fools and idle men, and the well-known events as background noise. Here, the one political truth is the human body that suffers and the powers that seek to use that suffering instead of relieving it. Tarare’s doctors quibble about ethics, pontificate about the Republic, ponder whether his state is supernatural and what that means for science. Meanwhile, he is poor, he is hungry, he wakes covered in blood. That is Blakemore’s revolution. For all its great intelligence, The Glutton is not a flawless novel. Most importantly, the character of Tarare never quite coheres. For the most part, he’s presented as a hapless, tender-hearted naif, borne from misadventure to misadventure without much grasp of what is happening. He is illiterate, unworldly, perceived as a simpleton by all around him. But he also serves as a vehicle for Blakemore’s elaborate, logophilic prose. Since the novel is in the third person, this clash is not entirely absurd; still, it can be jarring when he imagines “the holograph appendages of dragonflies”, realises he’s made a mistake “of potentially geopolitical significance”, or sees a woman in a fine dress as “panniered in a cumulus of white satin”. The main story is framed with scenes of Tarare on his deathbed, where he has become an urbane, cynical cannibal who takes pleasure in mocking and terrifying a teenage nun. Each of these versions of Tarare is enjoyable in itself, but for me they never came together to form an intelligible character. The plot and tone can also be unstable. Characters do extreme things without explanation. There are a handful of forays into magical realism that follow no discernible pattern, and a few too many reveries about the Day of Judgment and the dreams of maggots. In her intoxication with language, too, Blakemore can go too far. I wasn’t on board with the “carcinomic pinks” of a sunrise, or evening coming “stun-bright and violaceous”, and the reference to a man’s “monoceros haunches” lost me altogether. In one place, the mildness of Tarare’s character is “strung along on every timid shift of his bony lineaments, bared in the fallow of his eyes”. I’m not one who balks at a word like violaceous, but I often wished Blakemore had just done less. However, The Glutton’s weakest passages are more interesting than most novels’ strongest ones. If you add the wild story of Tarare to the setting of revolutionary France, and throw in the chaotic riches of Blakemore’s prose, The Glutton is certain to be one of the most remarkable novels of the year. As a reviewer, I generally give books away when I’ve finished writing about them. This one I will keep. The Glutton by AK Blakemore is published by Granta (£14.99). To support the Guardian and Observer, order your copy at guardianbookshop.com. Delivery charges may apply.