The New York Times has published an in-depth investigation into phone hacking at the News of the World and quotes sources stating that the then editor Andy Coulson was aware of what was going on.
The article claims: "Andy Coulson, the top editor at the time, had imposed a hypercompetitive ethos, even by tabloid standards. One former reporter called it a “do whatever it takes” mentality. The reporter was one of two people who said Coulson was present during discussions about phone hacking. Coulson ultimately resigned but denied any knowledge of hacking."
It also states: "One former editor said Coulson talked freely with colleagues about the dark arts, including hacking. “I’ve been to dozens if not hundreds of meetings with Andy” when the subject came up, said the former editor, who spoke on condition of anonymity. The editor added that when Coulson would ask where a story came from, editors would reply, “We’ve pulled the phone records” or “I’ve listened to the phone messages.”
The New York Times adds: "Sean Hoare, a former reporter and onetime close friend of Coulson’s, also recalled discussing hacking. The two men first worked together at The Sun, where, Hoare said, he played tape recordings of hacked messages for Coulson. At News of the World, Hoare said he continued to inform Coulson of his pursuits. Coulson “actively encouraged me to do it,” Hoare said."
Contacted by the New York Times, Bill Akass, the managing editor of the News of the World, dismissed “unsubstantiated claims” that misconduct at the paper was widespread and said that rigorous safeguards had been adopted to prevent unethical reporting tactics.
He accused The New York Times of writing about the case because of a rivalry with a competing media company. Presumably a reference to Rupert Murdoch's ownership of the Wall Street Journal.