Rupert Murdoch's Fox News television channel had a "black ops" department that may have illegally hacked private telephone records, a former executive for the station has alleged.

Dan Cooper, who helped launch Fox News as managing editor in 1996, said that a so-called "brain room" carried out "counter intelligence" on the channel's enemies from its New York headquarters, and that he was threatened after it found out he spoke to a reporter.

Another former senior executive told The Telegraph that the channel ran a Soviet-style spying network on staff, reading their emails and making them "feel they were being watched".

The channel, which has come under pressure amid allegations that outlets owned by Mr Murdoch may have attempted to hack the voicemail messages of 9/11 victims, firmly denies all the allegations.