David Cameron has said he was wrong to hire Andy Coulsen as his media chief in 2007 after the former editor of a Rupert Murdoch tabloid was found guilty of being part of a phone-hacking conspiracy.
Coulson was found guilty on Tuesday of conspiring to hack phones while working as editor of the News of the World. Rebekah Brooks, Coulson's predecessor, was acquitted of all charges by a jury at London's Old Bailey.
Coulson was hired by Cameron to be his media chief in 2007, as claims began to emerge that NoW journalists were routinely hacking into the voicemail systems of mobile telephones to gain stories.
Hours after the verdicts, the British prime minister said: "I'm extremely sorry that I employed him, it was the wrong decision," Cameron said in a "full and frank" apology.
"I asked him questions about if he knew about phone hacking and he said that he didn't and I accepted those assurances and I gave him the job."
The Coulson verdict threatens to damage Conservative leader Cameron's reputation ahead of a national election next year.
Coulson, 46, ran the British leader's media operations from 2007 until 2011. Cameron said he had given Coulson a second chance after the ex-editor's media career had ended, something he said he now realised was a bad decision.
Coulson denied wrongdoing before and after Cameron hired him. During the trial, Coulson said he had been aware of one hacking incident, but that staff had kept the widespread criminal activity from him.