Sweden's new anti piracy laws are based on an EU directive
Internet traffic in Sweden fell by 33% as the country's new anti-piracy law came into effect, reports suggest.
Sweden's new policy - the Local IPRED law - allows copyright holders to force internet service providers (ISP) to reveal details of users sharing files.
According to figures released by the government statistics agency - Statistics Sweden - 8% of the entire population use peer-to-peer sharing.
Popular BitTorrent sharing site, The Pirate Bay, is also based in Sweden.
The new law, which is based on the European Union's Intellectual Property Rights Enforcement Directive (IPRED), allows copyright holders to obtain a court order forcing ISPs to provide the IP addresses identifying which computers have been sharing copyrighted material.
Figures from Netnod, a Swedish firm that measures internet traffic in and out of the country, suggest traffic fell from an average of 120Gbps to 80Gbps on the day the new law came into effect.
Speaking to the BBC, Christian Engstrom, vice-chairman of the Swedish Pirate Party - said the drop in traffic was a direct result of the new law, but that it would only be a temporary fall.
"Today, there is a very drastic reduction in internet traffic. But experience from other countries suggests that while file-sharing drops on the day a law is passed, it starts climbing again.
"One of the reasons is that it takes people a few weeks to figure out how to change their security settings so that they can share files anonymously," he added.
Mr Engstrom acknowledged that the new legislation would scare a number off file-sharing, and that the odds of getting caught had increased, but said that the risks to illegal file-sharers were still quite low.
"We estimate there are two million file-sharing [computers] in Sweden, so even if they prosecuted 1,000 people to make an example of them, for an individual user it is still a very small risk."
However, for some, that risk is already a reality.
A number of book publishers in Sweden have applied to the courts, on the day the law came out, forcing an ISP to disclose the details of one file-sharer who, the publishers claim, has more than 3,000 audio books on his server.
Speaking to the BBC, Kjell Bohlund - chair of the Swedish Publishers' Association - said that until the new law was passed, they were virtually powerless to act.
"Before 1 April, the only thing we could do about illegal file sharing was to refer it to the police, who were very reluctant to take it on.
The Pirate Bay founders have denied the charges
"Now we can go get the courts to force ISPs to disclose the user information of an IP address.
"In two weeks time, we will know exactly who owns that IP. We can then do nothing, ask him to stop, or sue him for damages. We won't do this for small offenders, this is just for the big fish," he added.
Other companies are watching the case with interest, to determine what the court deems to be sufficient proof.
One action which began before the new legislation was the prosecution of four men accused of promoting copyright infringement via the hugely popular BitTorrent sharing site, The Pirate Bay.
The Pirate Bay hosts thousands of links to so-called torrent files, which allow for movies, TV programmes and applications to be shared online.
A verdict is expected later this month.
Mr Engstrom said the new law was "a disaster", not just for file-sharers, but for Sweden as a whole.
"Dealing with illegal file-sharing is a job for the police. It is their job to enforce the law.
"Now we have given private corporations the legal right to go after our civilians. That's not how Western democracies work," he said.
Mr Bohlund acknowledged that cracking down on illegal file-sharing was not a long-term solution.
"In a study, 80% of people thought we shouldn't go after file-sharers.
"But ask them how they feel about taking money out of the pockets of musicians, authors or artists and that number falls by a significant amount," he said.
"Ultimately we have to change people's perception on file-sharing."