Apple has allegedly fired at least five retail staff from its high-street stores after discovering that they had illegally downloaded the latest version of its Mac operating system.

Copies of Mac OS X 10.5 Leopard have been showing up online since they were handed out at Apple's Worldwide Developers Conference earlier this month.

The five retail staff were found discussing the benefits of the software and were asked if they had downloaded it, according to an anonymous statement by one of them on the Think Secret website.

"All of us know that we violated our NDA and ethics policy," the anonymous source said. "Therefore, because we had the character to tell the truth and to face the consequences of our actions, we were terminated."

However, the staff member who spoke out questioned Apple's decision. "My only question is, if we all lied and denied it would we still be working at Apple today? Even more so, is that the kind of person that Apple wants working for them?"

Apple had previously pursued three individuals through the courts when its OS X 10.4 Tiger software was found on BitTorrent file-sharing services, eventually settling out of court.