News International's new hacking evidence
BBC business editor Robert Peston on News International
I have learned that News International uncovered four e-mails indicating that the former News of the World news editor Ian Edmondson had full knowledge of the illegal phone hacking activities of the private detective, Glenn Mulcaire.
Glenn Mulcaire was jailed in 2007 for his role in trying to intercept voicemail messages left for royal aides.
Mr Edmondson had always denied to News International's bosses that he had any knowledge of hacking. So executives of the UK arm of Rupert Murdoch's News Corporation yesterday concluded that they had no option but to sack Mr Edmondson.
A source said that Mr Edmondson misled News International when originally asked about all this a few years ago. "He denied all knowledge," the source said.
News International is now expected to go on a hunt for evidence to discover whether other executives from that era are implicated.
"This is a new phase for News International in relation to the hacking," said a businessman close to the media group. "They want to know everything and root out anyone who obtained information improperly. It could get pretty messy."
Andy Coulson, the former director of communications for the prime minister who was editor of the News of the World at the relevant time, has always denied all knowledge of the hacking.
In investigating the involvement of Mr Edmondson, News International trawled through thousands of e-mails.
News International has passed the e-mails - described as "devastating" by a source - to the police, which has opened a new enquiry into the alleged illicit hacking of mobile phones of well-known individuals.
You can keep up with the latest from business editor Robert Peston by visiting his blog on the BBC News website.