A US lawyer for Jeremy Jaynes, once considered one of the world's top 10 spammers, has told the Virginia Supreme Court that the state's anti-spam laws are a violation of the freedom of speech protected by the First Amendment.

Jaynes was charged in 2003 in the nation's first felony case against illegal spamming for using aliases and false internet addresses to inundate email users with spam. He was found guilty and sentenced to nine years in prison.

Despite being from North Carolina, Jaynes was charged and convicted under Virginia state law as he had used servers located in that state.

"There is absolutely no question that spam can be regulated," said Jaynes's lawyer Thomas Wolf.

"The problem with Virginia's statute is that it attaches severe criminal penalties to unsolicited bulk email of a non-commercial nature."

Wolf explained that under these laws anyone around the world could unwittingly break the law by sending anonymous political or religious emails in bulk because some of the messages would probably pass through servers in Virginia.

However, state solicitor General William Thro argued that the law does not bar free or anonymous speech, but prohibits falsifying internet routing and transmission information to electronically trespass on a privately owned computer network.

Thro said that there is "no constitutional right to use the property of others to engage in speech" and that "using unsolicited bulk email to commandeer a privately owned computer network is akin to stealing a car to drive to a political rally".

Despite the controversy surrounding the law, the Virginia Court of Appeals upheld Jaynes's conviction last September in a unanimous ruling.

The court maintained that the statute "does not prevent anonymous speech but prohibits trespassing on private computer networks through intentional misrepresentation, an activity that merits no First Amendment protection".

The Supreme Court is expected to issue its ruling in November when Jaynes, who has remained free during his appeal under a $1m bond, may have to begin his sentence.