LONDON - Despite a newly enacted UK law cracking down on extreme porn, British police say they will not seek out owners of violent pornography unless there is "due cause".

Section 63 of the Criminal Justice and Immigration Act 2008 was passed following British mother Liz Longhurst's three-year campaign to curb violent sex videos. Longhurst's schoolteacher daughter Jane was murdered by Graham Coutts, a man who collected extreme porn.

The law criminalizes the possession of pornographic material that depicts necrophilia, bestiality, or life-threatening or body-injuring violence. Offenders face a maximum sentence of three years in jail.

According to British news sources, the Ministry of Justice has predicted few national prosecutions and placed responsibility for enforcing the law on local police departments.

"The police will not be actively targeting members of the public but will be conducting investigations into the unlawful possession of this material where found," Britain's Association of Chief Police Officers said in a statement to the press.

A 2007 British government review of research concluded extreme pornography can be linked to violence and pro-rape attitudes among the men who view it excessively. But opponents argue that the legislation will lead only to "harmless criminals and victimless crimes."

"People who abuse may look at extreme images, but looking at the pictures doesn't make you like that," said Clair Lewis, a spokesperson for the Consenting Adult Action Network.

Lewis called Coutts' murder of Longhurst "abysmal," but added that blaming violent actions on viewing pictures from the Internet is just a murderer's or rapist's "excuse."

"If this law had been in place a few years ago, it wouldn't have saved Jane," she said. "We're fighting a really emotive battle here, but there is no evidence that this law will work."

Likewise, the British free speech and human rights group Backlash sees the law as well-meaning but misguided.

"The law is infantilizing women and sets men up as rapists and this does nothing for gender relations," said spokesperson Alex Dymock. "Some fairly innocent images are going to be liable for prosecution with this law and I don't believe it will save any lives."