Most of her readers would agree, I think, that Jane Austen’s heroines, even the witty Elizabeth Bennet, do not indulge in hateful or spiteful talk. Of these good-mannered, good-natured women, Emma Woodhouse is the most self-confident, even to the point of self-congratulation, and thereby runs a risk, for her author sees presumptuousness as a fault to which even diffidence is preferable. The turning point of Emma and its most shocking moment is Emma’s slight but stinging gibe at poor, talky, tiresome Miss Bates. Miss Bates says:

“I shall be sure to say three dull things as soon as ever I open my mouth, shan’t I?” – (looking round with the most good-humoured dependence on every body’s assent) – “Do not you all think I shall?”

Emma could not resist.

“Ah! ma’am, but there may be a difficulty. Pardon me – but you will be limited as to number – only three at once.”

Miss Bates, deceived by the mock ceremony of her manner, did not immediately catch her meaning; but when it burst on her, it could not anger, though a slight blush showed that it could pain her.

Emma is not ashamed of this until Mr Knightley tells her, with controlled but passionate anger, that her words were cruel, that “it was badly done”. At this (the final blow of a disappointing, frustrating day) Emma is ashamed, indeed humiliated, grieved beyond words. And she cries silently in the carriage all the way home.

Well, that’s a different world from this one:

To Liz’s surprise, both Lydia and Kitty exclaimed with delight hearing at dinner of Charlotte’s charades invitation. “I hope you know I’ll kick your asses,” Lydia said, and Mary said, “By cheating, you mean?”

“What if we’re on the same team?” Liz asked. “Is your ass-kicking restricted to your opponents or is it indiscriminate?”

“Do you ever pass up a chance to use a big word?” Lydia replied. “Or do you find that circumlocution always magnifies life’s conviviality?”

“That wasn’t bad,” Liz said. “Especially for someone who scored as low as you did on the verbal part of the SATs.”

“Stop quarrelling, girls,” Mrs Bennet said. “It’s unbecoming.”

“They’d never speak to one another otherwise,” Mr Bennet said.

The five Bennet sisters and their parents speak to one another only in this style: peevish and self-assertive, relentlessly striving for wit through mere insult. Any differentiation of character is hard to perceive through the artificiality and monotony of the dialogue. Lydia and Kitty can be shown as more disagreeable than Liz and Jane only by the slightly greater coarseness of their language. If I were tempted to feel any sympathy for any of them – for Mary, perhaps, the plain, bookish, feminist one – I would be forestalled by the author:

But if you assumed that accompanying Mary’s supposedly scholarly interests was an open-minded acceptance of others, or that accompanying her homeliness was compassion, you’d be wrong. Mary was proof, Liz had concluded, of how easy it was to be unattractive and unpleasant.

Is proof needed? Is it hard to be both unattractive and unpleasant when one lacks beauty and natural amiability? Surely it is harder to be attractive and pleasant without those gifts – and yet people do manage it. None of them, however, could survive long amid the incessant sneers of the characters of Eligible, with the author hovering over them, pitiless as a horsefly, to deliver judgment.

I wondered what could possess a writer to tie her novel so blatantly and rigidly to a very well-known one – taking the general plot and the name of every character, so that comparison with the original becomes as unavoidable as it is crushing. I hadn’t realised that Sittenfeld’s book was part of an “Austen Project” that includes versions of Sense and Sensibility by Joanna Trollope, Northanger Abbey by Val McDermid and Emma by Alexander McCall Smith. We are in a period of copycatting, coat-tail-riding, updating and mashup; rip-off is chic, character theft from famous predecessors is as common as identity theft via credit cards, and everybody from Achilles to Tom Joad is likely to end up solving crimes, in bed with a vampire, or battling zombie hordes. This wholesale appropriation is now so widespread that it is clearly more than a fad or a cheap PR gimmick, though it is both of those. I have done it myself: I stole Virgil’s Lavinia, and his Aeneas, and Virgil himself along with them. I am not ashamed. I did it for love.

And that makes me believe that even this pointless trivialisation of Austen’s novel arose in part at least from love and admiration - that it is an effort, however ill judged, to reproduce the inexhaustible pleasure of reading Pride and Prejudice by rewriting it. It might have been wiser to emulate Borges’s friend Pierre Menard, who rewrote Don Quixote by doing so, word for word, beginning to end. As it is, Sittenfeld risks the humiliation that awaits presumption.

I will play Mr Knightley and say to her: it was badly done. But I don’t expect her to cry all the way home in the carriage. And she might well answer me, in the tone and spirit of her characters, that she’ll cry all the way to the bank.

• Ursula Le Guin’s Lavinia is published by Weidenfeld & Nicolson. To order Eligible for £11.99 (RRP £14.99) go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99.