In a move that will set a chill in the music and film industry's bones one of the US's top lawyers is set to take them to the cleaners claiming that file sharing on P2P networks is fair use.

For years the music and film industry avoided taking on Harvard students for file sharing, fearing that there were people there who could give them a run for their money because they would know the law. Now a top law professor Charles Nesson has revealed he will be defending a student against the RIAA by claiming that there is noting illegal about swapping files provided you don't make any money on the transaction.

Nesson is defending file-swapper Joel Tenenbaum and in court filings, revealed a doomsday strategy for the film and music business. If he wins, he will essentially legalize the sharing of all digital goods, copyrighted or not, by noncommercial users. He will argue that statutory damages only apply to commercial infringers.  The law offers rightsholders the chance to seek either statutory or actual damages, but that the two are meant to be equivalent.

If the two remedies are equivalent, and if "individual noncommercial copying results in no provable actual harm to the copyright harm holder," then actual damages would be zero-and so would statutory damages.

Fair use is defined by four factors and Nesson is confident he can give a jury evidence relating to each one. Another one of his defences is that the jury should consider "the copyright holder's knowledge of and assumption of risk when it published the copyrighted work that work would be ripped and shared on P2P networks."