Digital pirates, who for years have tormented the music and film industries, have found a new source of plunder in e-book publishing.

With the words “dan brown lost symbol torrent” and a few clicks, anyone can download the American author’s latest bestseller free via any of hundreds of web links.

This Christmas, e-book reading devices such as Amazon’s Kindle and Sony’s Reader will be among the most popular gadgets. But there are fears that as consumers get used to reading digital books they will look for a free download rather than pay.

In the US, where the Kindle has been available for two years, digital book piracy is booming. The web has enabled thousands of sites to distribute pirated book content free. American publishers are estimated to have lost more than $600 million (£363 million) last year to piracy.

Even before The Lost Symbol was published in September, pirated copies were circulating on the internet. Within a couple of days of its release filesharers had downloaded it more than 100,000 times.

British publishers are taking action to stop the pirates. The Publishers Association has released a web tool that allows publishers to log the details of an infringement of copyright. It then sends a demand to the offending website for the link to be removed. The portal has been alerted to more than 4,000 cases of online piracy by more than 40 publishers and has succeeded in taking down 2,638 illegal copies of books.

Alicia Wise, digital consultant to the association, said: “There are a lot of holes in the dyke. We are surprised by the scale and spectrum of authors that are being pirated. We need to get to grips quickly with practical ways of tackling copyright infringement.”

Book publishers are determined to prevent their business from being undermined in the same way as the music and film industries have. The relatively small digital file sizes for e-books provide an added incentive for filesharers. A film can be up to 1.5GB whereas the typical e-book is no more than 3MB, making it much easier to download.

George Walkley, digital strategy director for Hachette Livre UK, the biggest publisher in Britain, said that while the e-book business was booming, with a 300 per cent increase in titles available in the last year, so was piracy.

Some books, such as the Harry Potter series, were being pirated because they were not available in digital format and there was “frustrated demand”, he said. But all popular authors faced the prospect of illegal copies of their works being circulated on the internet.

Recent victims included Stephanie Meyer, Jasper Fforde, Iain Banks and Anthony Holden. “We are seeing a lot of piracy. It’s an important moment for the market,” Mr Walkley said.

The demand for e-books is certain to soar as more devices are released. Sony, Bookeen, Elonex, Samsung and iRex already offer e-readers. In the US an estimated 1.7 million people own one, and that number could rise to 4 million by the end of the year, according to analysts.

The increase in the use of smartphones is also expected to add to the demand. One out of every five new applications introduced for the iPhone last month in the US was for e-books, according to Flurry, a research company that studies mobile trends.

Apple is likely to increase the demand for reading books online when it releases its tablet computer early next year. Google’s new digital library will also boost the market, allowing readers to search millions of works, read extracts and buy copies.

Until recently publishers thought that books were relatively safe because it was so labour intensive to scan each page to convert a book to a digital file. But they have discovered thousands of cases of piracy on hosting websites such as Rapidshare. Users can upload any file and then share it by posting the link on blogs, forums or in e-mails with their friends.

Ms Wise said that publishers needed to come up with better ways for readers to buy digital books. “We are at a delicate moment. We have a chance to get our distribution models right against a difficult backdrop of piracy. We have to encourage book lovers to make ethical choices. We would hope that people who love books would make supportive decisions about how they acquire them.”

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