"The BBC hacked into 22,000 computers as part of an investigation into cybercrime but the move quickly backfired, with legal experts claiming the broadcaster broke the law and security gurus saying the experiment went too far.
The technology show Click acquired a network of 22,000 hijacked computers - known as a botnet - and ordered the infected machines to send out spam messages to test email addresses and attack a website, with permission, by bombarding it with requests.
Click also modified the infected computers' desktop wallpaper.
"Within hours, the inboxes started to fill up with thousands of junk messages," the BBC wrote on its website.
Of the website attack, the BBC boasted: "Amazingly, it took only 60 machines to overload the site's bandwidth.""