LONDON — The editor of Britain's Daily Mirror newspaper told a media ethics inquiry Monday it is possible illegal phone hacking took place at the tabloid, which was edited for almost a decade by CNN celebrity interviewer Piers Morgan.

The editor of sister title the Sunday Mirror told the same tribunal that she couldn't be sure illicit eavesdropping hadn't gone on there, too — but the papers' publisher said the company had no plans to launch an internal investigation into possible wrongdoing.

Mirror editor Richard Wallace had told the inquiry earlier that hacking "might well" have been going on at the Mirror in the early 2000s.

But he said he had no knowledge of it and insisted "ethical issues are embedded" within the culture of the paper's newsroom.

The judge-led inquiry into press standards was set up in the wake of revelations that Rupert Murdoch's now-shuttered News of the World had illegally eavesdropped on the voice mails of celebrities, politicians and even crime victims in its quest for scoops. Some alleged victims have accused other newspapers outside the Murdoch empire of wrongdoing, too.

Comments made by Morgan have raised suspicions that phone hacking may have been going on while he was in charge of the Daily Mirror.

Morgan told an earlier session of the inquiry that he didn't believe he ever listened to hacked voicemail messages while he was editor between 1995 and 2004.

Morgan told the committee his earlier comment that "loads of newspaper journalists were doing it" was based on rumor and hearsay.

But Morgan refused to explain how he had heard a voicemail message left by former Beatle Paul McCartney on the phone message system of his now ex-wife Heather Mills.

Morgan's description of the message in a 2006 article for the Daily Mail led some to wonder whether he'd obtained it through phone hacking. Mills has said there was no way Morgan could have obtained it honestly.

Wallace, who took over as editor after Morgan was fired in 2004 for running faked pictures of British soldiers allegedly abusing Iraqis, said he had never heard that message.

He acknowledged "it's possible" that phone hacking was the source of a 2002 story on the romantic life of Sven-Goran Eriksson, then England's national soccer coach.

Tina Weaver, editor of the Sunday Mirror, was asked about a BBC report that claimed phone hacking had gone on "pretty much every day" for a period at the newspaper.

"I don't believe it to be true," she said, but admitted the BBC's claim had never been internally investigated.

Sly Bailey, chief executive of the newspaper's publisher, Trinity Mirror PLC, acknowledged that after a News of the World reporter and a private investigator were arrested for phone hacking in 2006, "lots of journalists were speculating" about the extent of similar wrongdoing at other tabloids.

But she said that at the Mirror titles, "there was no evidence and we saw no reason to investigate."

And she said she didn't plan to investigate now.

"I don't think it's the way to run a healthy organization, to go around conducting investigations when there is no evidence," Bailey said.

The still-unfolding hacking scandal has sparked the resignations of several top Murdoch executives, senior police officers and Prime Minister David Cameron's spin doctor, a former News of the World editor.

The inquiry, led by judge Brian Leveson, is hearing this week from editors of daily newspapers and celebrity magazines including Hello! and OK!