Twentieth Century Fox has issued a legal summons to video website YouTube, after one of its users illegally uploaded entire episodes of hit TV show 24 before they were premiered on US networks. JANE SUNDERLAND, vice president of Fox entertainment group, believes the offending material - which includes 12 episodes of The Simpsons -could cause the company "irreparable harm". She admits Fox is unable to determine the users' identities without the help of YouTube and LiveDigital, a smaller video content site, and a subpoena against the two companies was filed last week (18JAN07). The 24 episodes appeared on YouTube prior to their primetime 14 January (07) premiere on the Fox broadcast network. Fox became aware the episodes were on YouTube six days earlier (08JAN07), according to the subpoena. YouTube and other similar video-sharing sites normally inform content providers they will delete copywritten material when alerted by the relevant parties.