A law firm hoping to secure the identities of Internet users who allegedly shared copyright material without permission is likely to find itself in a sticky situation today. The firm has reportedly approached ISPs in Australia with demands that they hand over subscribers' details, but according to their own published literature the company has little faith in IP address-based evidence.

Yesterday, Renai LeMay of Delimiter broke the news that mass piracy lawsuits are headed back to Australia.

LeMay revealed that a lawfirm has written a series of letters to major Aussie ISPs asking that they hand over the personal details of individuals said to have downloaded and shared their clients’ copyright material without permission.

After confirming with several sources, Delimiter revealed that the company in question is Sydney-based law firm Marque Lawyers.

So far, several of the ISPs contacted have informed Marque that they will not be handing over the information requested. In response the law firm said it is considering using the courts to force them to do so.

Delimiter contacted Marque both by telephone and email yesterday morning requesting an interview, but when we spoke with LeMay last night nothing had yet been heard back. However, when that call does come it is likely to be an uncomfortable one.

Yesterday morning, just after the Delimiter article went live, a tipster sent TorrentFreak an interesting document. Titled “It wasn’t me, it was my flatmate! – a defense to copyright infringement?” the paper, a newsletter published by Marque themselves, details the company’s stance on file-sharing accusations.

The paper begins with a potted history of the Joel Tenenbaum case in the United States but gets the facts wrong straight from the beginning.

“You may have heard that the US Supreme Court recently refused to hear the appeal of a college student who was ordered to pay $675K in damages for illegally downloading and redistributing thousands of songs through BitTorrent,” the Marque paper begins, wrongly mentioning BitTorrent and the number of songs in the case.

The company then moves on to the big issue of the day – U.S.-based companies who write to ISPs in the hope of identifying alleged pirates so that cash settlements can be obtained. This is where it gets awkward – really awkward.

Referencing a previous case in New York, Marque notes that a court refused to hand over the personal details of Internet subscribers to the plaintiff.

“The judge, rightly in our view, agreed with the users that just because an IP address is in

one person’s name, it does not mean that that person was the one who illegally

downloaded the porn,” Marque Lawyers write.

“As the judge said, an IP address does not necessarily identify a person and so you can’t

be sure that the person who pays for a service has necessarily infringed copyright.”

The law firm then goes on to back up its assertion with scenarios in which the account holder would not be the infringer.

“For example, in an office or at home, where there is a WiFi connection, only one IP

address will be allocated to that wireless connection. This means that every user of each

device (computer, iPad, iPhone etc) connected to that WiFi connection will use the same

IP address. Even a random passerby accessing the WiFi network would be using the

same IP address,” the company explains.

“This decision makes a lot of sense to us. If it holds up, copyright owners will need to be a whole lot more savvy about how they identify and pursue copyright infringers and, perhaps, we’ve seen the end of the mass ‘John Doe’ litigation,” they conclude.

The big question is whether Marque’s clients have indeed become “more savvy” or whether they still intend to rely on IP address-only evidence. If so, the Marque Lawyers document (which can be downloaded here and also from Marque’s own server) will come in very handy for letter recipients.

If the lawfirm writing the letter doesn’t believe that the evidence is up to much, there’s no reason the recipient should either. A simple denial is going to be difficult to argue with.