LONDON — CNN celebrity interviewer Piers Morgan refused to disclose details Tuesday about his most damning link to Britain’s phone hacking scandal — his acknowledgment that he once listened to a phone message left by Paul McCartney for his then-wife Heather Mills. In an eagerly awaited appearance before the U.K.’s media ethics committee, Morgan, who replaced Larry King on CNN, was visibly tense, sometimes hostile and often rejected characterizations of his actions made by inquiry lawyers as “nonsense.” The stakes were high for Morgan. More than a dozen journalists have been arrested, senior executives with Rupert Murdoch’s News Corp. media empire have lost their jobs, and top U.K. police officers have resigned over their failure to tackle the phone hacking scandal. His testimony Tuesday was given under oath, and Morgan could be subject to criminal proceedings if he was found to have violated any British laws. Before his U.S. television career, Morgan ran two British tabloids — first Murdoch’s News of the World and then the Daily Mirror, owned by Murdoch competitor Trinity Mirror. A key line of questioning centered on comments Morgan made in a 2006 article in the Daily Mail tabloid. In it, Morgan said he was played…