Acid-Lounge.com

Advocates of open source software have hailed a court ruling protecting its use even though it is given away free.

The US federal appeals court move overturned a lower court decision involving free software used in model trains that a hobbyist put online.

The court has now said conditions of an agreement called the Artistic Licence were enforceable under copyright law.

"For non-lawgeeks, this won't seem important but this is huge," said Stanford Law Professor Larry Lessig.

"In non-technical terms, the Court has held that free licences set conditions on the use of copyrighted work. When you violate the condition, the licence disappears, meaning you're simply a copyright infringer.

"This is a very important victory."