Just one letter separates the insulting but otherwise harmless word “twit” from one that is equally insulting but cut from a distinctly coarser cloth. But that letter has led to a supermarket chain removing a book from its shelves, the publisher agreeing to remove the offending word from the next edition and one of Britain's bestselling authors being made to look rather foolish.

The decision by Random House to remove the word from Jacqueline Wilson's My Sister Jodie followed a complaint from Anne Dixon from Co Durham, who bought a copy of the book as a gift for her great-niece Eve Coulson, aged 9.

As a precaution - to make sure that the book was not too sad for Eve, not to check for obsenity - Mrs Dixon, 55, decided to read it herself. “I got to the page where the reference was made to a ‘toffeenosed twit',” she said. “On the next page the word changed. I thought I was mistaken, but I saw to my shock it had been repeated twice again.

“I am not a prude. In fact, I am quite broadminded, but this is completely inappropriate for children. They should not have to be subjected to trash and vulgarity.

“I did not expect this from a well-respected author and do not want my young niece to have to see this obscene slang.”

Mrs Dixon sent an e-mail to Dame Jacqueline but when she did not reply she complained to the Stanley branch of Asda, from which she had bought the book. Asda has now withdrawn the title from its stores nationwide until it is amended by Random House.

Perhaps the reason for Dame Jacqueline's failure to reply was sheer embarrassment. According to Random House sources, she was unaware of the word's reference to the female genitalia. Her dictionary, The Times was told, listed it as meaning “a foolish or despicable person”.

If so, she is in good company. The poet Robert Browning included it in his dramatic poem Pippa Passes (1841), under the mistaken impression that it meant some kind of nun's headwear: “The owls and bats/ Cowls and twats/ Monks and nuns/ In a cloister's moods.”

The popular theory is that Browning was misled by a scurrilous poem of 1660, which included the couplet: “They'd talk't of his having a Cardinall's Hat/ They'd send him as soon an Old Nun's Twat.”

Dame Jacqueline, who has sold more than 20million books in Britain and whose stories have been translated into more than 30 languages, also has the support of John Simpson, the chief editor of the Oxford English Dictionary. He said: “I do not think it is felt to be the worst swear word in the language. It is used to mean a mere fool without any indication of what its original meaning is. I am a bit surprised that it has been taken out.”

A spokeswoman for Asda said: “The publisher is aware of the word that is featured in the book and has agreed that it's not appropriate for children and will be reprinting copies. As soon as these copies are available we will stock them in our stores.”

A spokeswoman for Random House said: “We are very sorry if anyone is offended by the language. Jacqueline Wilson aims to reflect the realities of modern life. In the context of the character we felt the word was used in a way that accurately portrayed how children like Jodie and her friends would speak to each other. We have sold over 150,000 copies of the book since March this year and have only received three complaints.”

She said that the decision to change the book had been taken before Mrs Dixon's complaint.

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