This issue concerns a case between five audiobook publishers and the Swedish ISP ePhone which appealed a lower court ruling ordering the firm to hand over information about the users connected to certain IP-addresses.

The Swedish Supreme Court (Högsta Domstolen - HD) has now taken up the case and has requested the parties involved to submit their view on whether it is necessary to send the matter for a preliminary ruling to the European Court - decision interpreted by experts to mean that the case is headed for Luxembourg, a process that can take years.

"I think so clearly. Apparently HD has made a preliminary assessment and concluded that most factors indicate that the issue be sent to Luxembourg," said Daniel Westman, a legal expert in file sharing at Stockholm University.

The parties may also be given an opportunity to comment on a draft of the request in a decision which has surprised Magnus Nytell, CEO of audiobook publisher Bonnier Audio.

"It has unexpectedly turned out this way. Granted, it is a new law and it is important that you put your foot down in various directions as it has implications for the future but we thought it was pretty clear that we would be given the Ipred-addresses (sic)," he said.

Bo Wigstrand, president of ePhone, sees the Supreme Court decision as a victory. The firm has previously argued that the case should be considered by the EU court in Luxembourg.

"We have drawn the conclusion that it is now clear that this issue will be sent to Luxembourg, and if the court does take this up it will mean a review of how the Ipred law is used in Sweden," he said.

Wigstrand argued that the law provides for private surveillance in an area that should be the reserve of the police and he does not expect to be forced to hand over his customer's IP information to the publishers.

"One should not claim success in advance but this shows that you can not have laws in which private investigators undertake these types of investigations. The police should do it."

When the new Swedish law came into force on April 1st, the five publishers of audio books were the first copyright holders to file a case under the new measure.

The publishers, which include 15 authors who suspected their work has been spread illegally over the internet, demanded to know who owned a server suspected of containing some 2,000 audio book titles.

But ePhone refused to reveal who was using the IP-address in question, pointing out that a password was required in order to gain access to the works stored on the computer.

As a result, the company argued, the sound files weren’t publicly accessible and thus the matter wasn’t a case of copyright infringement.

The publishers then sought a court order which would force ePhone to divulge information about the users tied to the IP-address.

The Solna district court first ruled in June 2009 in favour of the publishers but the the Court of Appeal (Hovrätten) upheld ePhone's appeal of the decision, ruling that the publishers were unable to prove whether the audio books on the server really had been available to the public.

ePhone and the audiobook publishers are required to submit their response to HD before July 5th, with any decision over whether to proceed to Luxembourg expected to take some time.