Internet traffic in Sweden has plummeted after a tough new anti-piracy law was enacted in the country earlier this week, casting interesting new light on the extent of illegal file sharing.

The new law requires copyright holders such as record and entertainment companies to go through the courts to determine the identities of those suspected of piracy, via their IP addresses.

The anonymity that illegal file sharers have enjoyed made the practice widespread, although figures vary as to exactly how commonplace it is in various countries.

However, traffic to Netnod Internet Exchange AB, a Swedish firm which manages many of the country's key internet exchanges, reported a drop of around half since Wednesday, when the law took effect. Throughput has yet to pick up.

Data transmission rates have slumped from a peak of 190Gbit/s to 200Gbit/s to daily highs since Wednesday of about 100Gbit/s. At the time of writing, the figure was around 80Gbit/s.

Along with its Scandinavian neighbours, Sweden has one of the most mature internet industries in the world, with a highly developed fibre-optic broadband infrastructure. The figures will be a shock to many, as they point a potentially high prevalence of illegal file sharing.

France yesterday showed its commitment to eradicate illegal file sharing after passing a 'three strikes law' which decrees that persistent offenders can be suspended from using the internet for a period of time. However, moves to get the law enacted at a European level have met with more opposition.

UK communications minister Lord Carter's Digital Britain interim report released in January proposed the creation of a Rights Agency to deal with the problem of the illegal copying and sharing of music and films over the internet.

However, controversially, he stated that the funding may have to come from ISPs, which in turn could pass the costs on to customers.

Last summer, six leading UK ISPs agreed to establish a code of practice for dealing with the sharing of copyright material over the internet, to be developed in conjunction with the Department for Business, Enterprise and Regulatory Reform.