The practice of illegal online downloading suffered a devastating blow when the Federal Court of Australia recently ordered Australian internet companies to reveal the IP addresses of thousands of account holders who illegally uploaded the film “The Dallas Buyers Club’’ online.

Justice Nye Perram did not impose any limit to the amount of damages that the copyright holder of the Oscar-winning film could claim directly from each individual – which stands at more than 4,726 users and includes their names, IP addresses and residential addresses.

Perram said the details of the individuals had to be kept private by the film makers.

Internet companies iiNet Limited, Internode, Amnet Broadband, Dodo Services, Adam Internet and Wideband Networks were all affected by the ruling.

“I will also impose a condition on the applicants that they are to submit to me a draft of any letter they propose to send to account holder associated with the IP addresses which have been identified,’’ said Perram in his ruling, “The applicants will pay the costs of the proceedings.”

The internet service providers have yet to reveal whether they plan to appeal the ruling in the designated 28 days.

iiNet has warned its customers to expect speculative invoicing – an ‘intimidating’ letter demanding significant sums of up to $7,000 for an alleged infringement, or threatening higher costing court action.