More than a third of bestselling ebooks are priced higher than their hardcover versions, says a survey of the books traded online by Amazon.
Experts and consumers are outraged by such a disparity in prices as electronic versions should be far cheaper because they cost nothing to print, store or transport.
The findings are also all the more controversial as they come after a landmark European Union ruling that publishers may have illegally colluded to raise ebooks prices, according to the Daily Mail.
J.K. Rowling's new book for adults, "The Casual Vacancy", costs nine pounds if ordered on Amazon with its discount of 11 pounds on the original publisher's price. The ebook version, however, is being sold on the same website for 11.99 pounds.
"The Chronicles Of Downton Abbey", a book sold alongside the TV series, costs 10 pounds in hardcover but 12.99 pounds for Kindle - an increase of almost a third.
ebooks make up about 15 percent of books sold in Britain, a market which is estimated to be worth 260 million pounds this year.
Amazon amounts to as much as 80 percent of the ebook market.
Publishers admit they save more than five percent on titles sold as ebooks, although they pay extra in value-added tax for the electronic versions.
Tom Tivnan, from industry experts The Bookseller, said: "A price of two to three pounds off the average selling price, including discounts, would be a fair price that the public would be more willing to pay for ebooks.
"If you can get "The Casual Vacancy" for 10 pounds in hardback, publishers should try to price the ebook around 7-8 pounds."