By Marcus Leach

Tyler and Cameron Winklevoss, the twin brothers who claim the idea for Facebook was stolen from them by Mark Zuckerberg, have been told by a US appeals court that they cannot back out of the settlement deal they made with the website.

The brothers, who claim Zuckerberg stole their idea whilst he was working for them on their ConnectU site in 2003, signed a legal settlement in 2008 worth £42 million, but in January had asked for it to be re-opened.

However, the US court declared there was no reason to re-open their case against Facebook, who themselves rejected the twins' claims.

"The Winklevosses are not the first parties bested by a competitor who then seek to gain through litigation what they were unable to achieve in the marketplace," three Ninth Circuit Court of Appeals judges said in the ruling.

"At some point, litigation must come to an end. That point has now been reached."

The twins claim that Zuckerberg stole the coding for their social networking site, ConnectU, and used it to launch Facebook.

Facebook agreed to a settlement in 2008 in order to end "rancorous litigation", however they did not admit Mr Zuckerberg had taken the twins' idea.

The Winklevosses received $20m in cash and $45m worth of stock valued at $36 per share in the deal.