Internet retailer Amazon has apologised for thousands of books about gay and lesbian topics losing their sales ranking over the past few days after they have been labelled as “adult” books.

Amazon previously ranked all books based on sales but over the past few days, thousands of books on gay topics have disappeared from the list.

The company previously told American author Mark Probst, whose sales were affected by the choice, that adult-themed books were removed from listings “in consideration of our entire customer base”.

However, Patty Smith, director of corporate communications for the company, said last night:

“This is an embarrassing and ham-fisted cataloging error for a company that prides itself on offering complete selection.

“It has been misreported that the issue was limited to Gay & Lesbian themed titles – in fact, it impacted 57,310 books in a number of broad categories such as Health, Mind & Body, Reproductive & Sexual Medicine, and Erotica.

“This problem impacted books not just in the United States but globally. It affected not just sales rank but also had the effect of removing the books from Amazon’s main product search.

“Many books have now been fixed and we’re in the process of fixing the remainder as quickly as possible, and we intend to implement new measures to make this kind of accident less likely to occur in the future.”

Authors including E.M. Forster, James Baldwin and even Dr Who and Torchwood star John Barrowman saw their books disappear from sales rankings.