A Belgian court has made the unprecedented ruling of declaring Internet Service Providers (ISPs) responsible for illegal peer-to-peer (P2P) file-sharing via their networks.

The June 28 ruling, in a case originally brought by Belgian collection society Sabam against ISP Scarlet, is the first of its kind in Europe.

And since it has taken place in the European Union, the ramifications could spread across the EU's other 26 states.

The judgment at the Brussels-based Court of First Instance declared that ISPs are obliged to use existing technology to either block or filter unauthorized copyrighted music distributed across P2P networks.

The judge, C. Heilporn, gave Scarlet up to six months to implement the anti-piracy measures. It will be fined €2,500 ($3,405) for every day it fails to comply after the six months.

The court dismissed Scarlet's argument that it was not responsible for the activities of its customers on the network. It also rejected the ISP's fears of invading all subscribers' privacy by monitoring customers' activities for copyright infringement.

The judgment recommended that Scarlet install filtering software developed by U.S.-based Audible Magic to prevent copyright abuse. It also offered six other possible technological solutions highlighted in a specially commissioned report.

In 2004, Sabam obtained an intermediary judgment acknowledging that subscribers of Tiscali (since rebranded Scarlet) were using the ISP to infringe copyright through P2P services.

The court then commissioned an expert to come up with technology solutions for blocking only illegal content. On Jan. 3, the expert came forward with 11, of which seven were relevant specifically to Tiscali (since renamed Scarlet).

"The court has confirmed that the ISPs have both a legal responsibility and technical means to tackle piracy. This is a decision that we hope will set the mould for government policy and for courts in other countries in Europe and around the world," said John Kennedy, chairman/CEO of international music-industry trade body IFPI, in a statement.

IFPI estimates about 20 billion illegal files were shared on P2P services in 2006 alone. This amounted to about 20 times the number of legal music downloads.