London: If you are an author whose book fails to grip in the opening chapter, it could prove costly.

Amazon is to begin paying royalties to writers based on the number of pages read by Kindle users, rather than the book they download. If a reader abandons the book a quarter of the way in, the author will get only a quarter of the money they would have earned if the reader had stuck it out.

Some authors believe it sets a dangerous precedent, while concerns have also been raised about the amount of data Amazon is able to mine from customers. Amazon claims its method is a fair way of rewarding authors who write lengthy books but have previously earned the same as someone who crafts 100 pages.

“We’re making this switch in response to great feedback we received from authors who asked us to better align payout with the length of books and how much customers read,” the company said. “Under the new payment method, you’ll be paid for each page individual customers read of your book, the first time they read it.”

To prevent authors beating the system by enlarging the type and spreading out their work over a larger number of pages, Amazon has developed a ‘Kindle Edition Normalised Page Count’ which standardises font, line height and line spacing. The new system, due to begin on July 1, initially applies to authors who self-publish their book via the Kindle Direct Publishing Select (KDP Select) programme, which makes books available to download from the Kindle library and to Amazon Prime customers.

Hari Kunzru, the award-winning author of ‘The Impressionist’, said the system “feels like the thin end of a wedge”. Peter Maass, a writer and editor, said on Twitter: “I’d like same in restaurants — pay for how much of a burger I eat.”

If the system spread to cover every book available for download, some popular authors would find their income significantly curtailed. The ‘Goldfinch’, by Donna Tartt, was one of 2014’s biggest sellers, but data released by Kobo, a rival to the Kindle, showed that only 44 per cent of readers who downloaded it read to the end.

Kerry Wilkinson, whose Jessica Daniel crime series propelled him to the top of the Amazon best-seller list as a self-published author, believes the system is fair.

“If readers give up on a title after half a dozen pages, why should the writer be paid in full?” he said. “If authors don’t like it, they don’t have to use KDP Select. It’s opt in, not opt out.”

But Wilkinson said he found it “eerie” that Amazon was keeping tabs on what — and how — you are reading. “Every time a reader is online, Amazon can see what they’re up to,” he said. “Even if it’s anonymous, that’s a lot of data mining.”