Viacom - whose brands include MTV and Nickelodeon - says Google, which owns YouTube, is illegally using its shows.

It said YouTube was guilty of "massive intentional copyright infringement".

Viacom alleges that about 160,000 unauthorised clips of its programmes have been loaded onto YouTube's site and viewed more than 1.5 billion times.

As well as more than $1bn in damages, the legal action seeks an injunction to prevent future copyright infringement.

'Clearly illegal'

"YouTube's strategy has been to avoid taking proactive steps to curtail the infringement on its site," said Viacom in a statement.

"Their business model, which is based on building traffic and selling advertising off of unlicensed content, is clearly illegal and is in obvious conflict with copyright laws."

Last month, Viacom, which also owns cable networks VH1 and Comedy Central, told YouTube to remove 100,000 "unauthorised" clips.

Viacom said its demand came after YouTube and Google failed to install tools to "filter" the unauthorised video clips following negotiations.

"There is no question that YouTube and Google are continuing to take the fruit of our efforts without permission and destroying enormous value in the process," it said.

"This is value that rightfully belongs to the writers, directors and talent who create it and companies like Viacom that have invested to make possible this innovation and creativity."

Doing deals

Google has yet to respond to Viacom's court action.

However, last week, its chief legal officer David Drummond said that it did obey copyright laws, resulting in "more exposure and in many cases more revenue for authors, publishers and producers of content".

The company, which paid $1.65bn for YouTube last year, has been trying to win permission from media companies to broadcast output legally on YouTube in exchange for payment, avoiding the threat of legal action.

Separately, the BBC has struck a content deal with YouTube to showcase short clips of BBC content.

The BBC hopes that the deal will help it reach YouTube's monthly audience of more than 70 million users and drive extra traffic to its own website.