In Jane Austen's day, a walk in the countryside could be dangerous, not just because one might catch a life-threatening cold.

Back then, landowners were not squeamish about shooting strangers on sight. Even worse were the mantraps they set to catch trespassers. None of Austen's characters ever falls into one of these lethal devices, but one certainly wishes they would snap around the ankles of modern authors who dare set foot on Austen's territory. Stealing grouse or salmon is as nothing to the depredations such writers make on her private ground.

Joanna Trollope is only the latest to step on to Austen's land, but within a page or two she has already asserted her right to be considered one of the worst offenders. Commissioned with other novelists such as Alexander McCall Smith and Val McDermid to rewrite Austen's oeuvre, Sense and Sensibility is her take on Austen's tale of passion tempered, in the shape of Eleanor Dashwood, and passion unfettered in the form of her tempestuous younger sister Marianne.

Trollope has expressed the wish that novels such as this might tempt new readers to tiptoe back to the originals. Any reader of true sense and sensibility will, however, hurl this anodyne version aside, and head straight for the real thing. Trollope's set of puppets, bearing the names and quirks of Austen's creations, jerk their way through a contrived contemporary tale that ticks most of the boxes of Austen's plot, and manages to desecrate one of the most interesting, comic, and beautifully written novels of the 19th century.

Its worst crime, perhaps, is that it is boring. The three Dashwood sisters, and their bohemian mother Belle, are obliged to leave their uncle's stately home when their father dies, and the house goes to their half-brother John. Eleanor must give up her training as an architect, Marianne her country views, and Margaret her school chums as they relocate to a bungalow on a friend's estate in Devon. What ensues, as Edward Ferrars makes his tentative appearance, and Willoughby roars on to the scene in full Byronic mode in his Aston Martin, is a pantomime that, while showing Trollope's dexterity in plotting, only serves to highlight the ineffable, inimitable brilliance of Austen's eye and ear.

It is not entirely Trollope's fault that in her hands the ghastly John Dashwood's wife becomes a caricature, as does kindly, insensitive Mrs Jennings. Nobody can conjure up these people as Austen did, because these were her characters. In the early 1800s, such people did exist, and rather than being merely laughable, their behaviour mattered, blighting as it did the lives of poorer relatives. Those with land and money held the reins in the Georgian era, whereas for a man such as Edward Ferrars to be scared of his mother, and unable to make some sort of a living in the 21st century, makes him not attractively diffident but pathetic. Meanwhile, in concocting devilry sufficient to turn Willoughby into the villain of the piece, Trollope descends into a level of urban melodrama that would grace an episode of The Wire.

But it's less the drama that makes this novel unbearable, more its mundanity. To read a sentence such as "Even in wet jeans he looked magnificent." is to feel the literary equivalent of the sack of Rome. It is little short of sacrilege to poach characters and plot, and to demean them and their author in this fashion.

Out of context, Sense and Sensibility loses all meaning, transformed from a witty, flint-edged tale about women's survival in a harsh world, into a sickly romance. Unlike music, novels are far more difficult to rework or improvise for a new age. Trollope may suggest that money and commonsense still play as large a part in a happy marriage as in Austen's times, but society 300 years ago was so different that to transplant this story wholesale, as she does, is pointless.

Trollope's problem is not that her version lacks respect, but that it is too dutiful, too clearly the work of someone who dare not kick over the traces. Austen, however, was a true radical. Mocking the gentry and aristocracy then was anarchic, and dangerous. To do so today is dull. Heretical though the idea of a rewrite seems, in the hands of someone wickedly inventive, a reimagining of the tale might conceivably work. This one, however, does not. Where's that gamekeeper!