Ten years after the passing of the Child Online Protection Act the law has again been ruled unconstitutional by the courts.

The Third US Circuit Court of Appeals in Philadelphia upheld a 2007 decision that the Act was overly broad and that parental monitoring software and filtering software was a better way to protect children.

"For years the government has been trying to thwart freedom of speech on the internet, and for years the courts have been finding the attempts unconstitutional," said Chris Hansen, senior staff attorney with the American Civil Liberties Union First Amendment Working Group.

"The government has no more right to censor the internet than it does books and magazines."

The Child Online Protection Act was introduced by Bill Clinton in an attempt to regulate pornography on the internet. It requires commercial sites in the US not to publish "material harmful to minors".

The court system has consistently ruled that the law violates the First Amendment and limits free speech.