LONDON (Reuters) - British lawmakers on Thursday called for U.S. talk show host Piers Morgan to return to Britain to answer questions about phone-hacking after allegations made by the ex-wife of former Beatle Paul McCartney.

Heather Mills' claims that a journalist had listened to voicemail messages on her mobile phone has added fuel to the flames of a scandal that has engulfed Rupert Murdoch's News Corp empire and much of the British establishment.

In an interview with the BBC on Wednesday, Mills said a journalist working for British publisher Trinity Mirror, owner of the Daily Mirror tabloid newspaper, had confronted her with details of a message left by McCartney on her phone in early 2001 following a row.

She said the journalist -- who was not Morgan, a former newspaper editor -- had admitted hacking her phone.

So far, allegations about the hacking scam have been mainly limited to the News of the World newspaper, owned by News Corp's British newspaper arm News International. The Sunday tabloid was closed last month amid public fury after it emerged that hacking victims included a missing schoolgirl later found murdered and other victims of crime.

Mills' claim widened the hacking scandal to other titles and turned the spotlight on Morgan, who once edited the News of the World and then the Daily Mirror until 2004. He said in a 2006 article for Britain's Daily Mail newspaper that he had listened to one of Mills' phone messages.

Morgan, now a chat-show host for CNN in the United States, issued a statement denying any wrongdoing.

"Heather Mills has made unsubstantiated claims about a conversation she may or may not have had with a senior executive from a Trinity Mirror newspaper in 2001," he said, describing her claims as "somewhat extravagant."

"To reiterate, I have never hacked a phone, told anyone to hack a phone, nor to my knowledge published any story obtained from the hacking of a phone," he added.

Therese Coffey, a Conservative legislator who sits on a parliamentary committee investigating phone-hacking, said Morgan needed to do more than issue statements from the United States.

"I just hope that the police take the evidence and go with it and if Mr Morgan wants to come back to the UK and help them with their inquiries -- and I don't mean being arrested in any way -- I'm sure he can add more light," she told the BBC.

Harriet Harman, deputy leader of the opposition Labour Party, said Morgan had questions to answer.

"It's not good enough for him to say, or somebody to say on his behalf, I always comply with the law, the Press Complaints Commission (newspaper watchdog) code of conduct," she told Sky News.

(Reporting by Michael Holden; Editing by Janet Lawrence)

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