In the latest development in the dispute between Apple and the author of a two non-fiction Danish books about hippies that contain graphic images, the computer firm has pulled the books' accompanying app.

“This is far worse than the original issue of them not publishing our book because it had pictures of naked people,” Peter Øvig Knudsen, author of ‘Hippierne 1’ and ‘Hippierne 2’, said in a statement.

He added that unlike when the books were pulled, an Apple representative did speak with a member of his staff, but no reason for the decision was given.

The companion app contained music, narratives, photography and historical film clips related to hippie culture in Denmark.

Apple’s move is the most recent development in a controversy that has national and EU lawmakers calling on the company to explain why it chose to pull the content by the respected Danish author.

Apple has so far declined to comment, although it is believed that the reason is because the book and the app contain pictures of nude people and sex acts.

Danish MEP Morten Løkkegaard (Venstre) however, has said that given the size and control that Apple has over the market for online books and apps, it needed to accept that there were cultural differences in its various markets.

“It’s not just about corporate rights. This form of censorship has political implications as well,” Løkkegaard said. “Apple can’t just walk into any country they want with an American ‘cowboy attitude’ and bark morals at people.”

The culture minister, Uffe Elbæk (Radikale), has also voiced his discontent. After initially declining to comment on the grounds that the matter had to do with a business relationship between an author and a retailer, he wrote on Facebook that he was “amazed” Apple hadn’t stated its position.

“Apple should explain itself,” he wrote. “Anything less than that is unacceptable.”

But others have questioned the controversy altogether. Ben Hammersley, a member of a European Commission panel looking into ways to secure internet freedom, insisted that Apple was within its rights to remove any works it deemed inappropriate.

“It’s like buying advertising space in a newspaper,” Hammersley explained, and drew a hypothetical example. “Let’s say I want to print an advert for my photographic history of cartoons featuring Queen Margrethe’s sexual adventures with the prophet Mohammed. If that newspaper in turn, decides that that’s not the sort of content the paper wants to be associated with and turns it down, is that censorship?”

This is a point that the European Commission’s Digital Agenda, which helps European residents and businesses get the most out of computer technologies, also agrees with since the European Union now has the authority to interfere with corporate rights and regulations.

“This is a complex matter. However, companies have the right to refuse any content they do not wish to be associated with, or any forms of expression inconsistent with their own beliefs and values,” Linda Cain, a Digital Agenda spokesperson, said.

Knudsen and his company, Hippieselskabet, used 200,000 kroner to make the app. And while Knudsen's creative director, Christian Kirk Muff, admitted that it could be reworked to suit Google’s Android platform – Apple's primary competitor, which has no guidelines for content – Muff argued that the costs of doing so outweighed the benefits.

“It would cost us a further 100,000 kroner to develop a Google app. How is that a sensible investment?” he asked.

See all the pictures in their censored and uncensored versions.

See other examples of works Apple has pulled from its online retail outlets