Online retailer Amazon has said digital versions of books have outsold physical copies for the first time ever.

On December 25, the internet company saw a spike in the sales of e-books as consumers who’d received an electronic reader as a Christmas present, searched for content to upload to their new device.

Kindles, Amazon’s own electronic readers, have become the most gifted item in the company’s history. Amazon would not release sales figures, but one analyst believes the firm is on track to sell a little over 500,000 Kindles by the end of the year, according to a report in The Guardian.

Amazon’s shares have benefited from a strong performance over the festive period, with sales peaking on December 14, when customers across the world bought 9.5m items – the equivalent of 110 products a second.

The Guardian said the popularity of e-books has increased in the UK over recent months. Amazon’s Kindle went on sale in Britain in mid-October and department store chain John Lewis has reported strong sales of a rival e-reader manufactured by Sony.

About 390,000 titles are now available to download from the Amazon Kindle store.