Sienna Miller was today expected to become the latest public figure to join the legal assault on Scotland Yard and the News of the World over the phone-hacking scandal. 
 
 Lawyers for the actor, whose private life has long been a tabloid staple, said she was ready to join the former deputy prime minister John Prescott and others in asking the courts for a judicial review of the police's conduct of the case. 
 
 Sources at the News of the World said she had taken the first step towards suing the paper for invading her privacy by allegedly listening to her voicemail messages. 
 
 The legal moves came after Miller, 28, discovered that the paper's private investigator, Glenn Mulcaire, had procured her mobile phone numbers, account number and secret PIN code, needed to intercept the voicemail of the minority of people who change the factory settings on their phones. 
 
 It also emerged today that Sean Hoare, a former News of the World journalist who told the New York Times and the BBC about hacking at the paper under Coulson, has been interviewed by police under caution. Lawyers said this indicated he was being treated by police as a suspect. "An interview under caution would follow someone being arrested as a suspect, except in the most exceptional circumstances," said Peter Lodder QC, a criminal barrister. 
 
 Paul McMullan, a second former News of the World staffer who told the Guardian that hacking was rife at the paper, was also contacted by detectives and told that they would like to question him under caution. 
 
 Scotland Yard has had the information about Miller being targeted in its possession since August 2006, when Mulcaire was arrested and his records seized, but failed to say anything to Miller until her lawyer, Mark Thomson, of Atkins Thomson, wrote to ask them. Even then an answer was delayed for 14 weeks. 
 
 Thomson said: "Our client only discovered that the Metropolitan police held this information on 15 October 2009 in response to our letter of 10 July 2009."Miller had previously sued the News of the World for invading her privacy by running intrusive stories about her relationships and publishing photographs of her in a bikini in Italy and of her filming a nude scene on a closed set. 
 
 In 2008, the paper settled the claims by paying her damages and sending her a written acknowledgement that they had been wrong to publish stories and photographs about her private life. 
 
 Friends of Miller said she had noticed warning signs with her voicemail, including new messages being recorded as old before she had listened to them. 
 
 For this reason, they said, she had changed her mobile number, but the material seized from Mulcaire suggested he had been able to discover her new number. 
 
 Former staff at the News of the World say Mulcaire was able to obtain confidential information from mobile phone companies and British Telecom. 
 
 Miller plans to join the legal action being run by Bindmans law firm to seek a judicial review of Scotland Yard's failure to warn potential victims of the hacking. 
 
 Those already involved in the action include Prescott, Brian Paddick, a former deputy assistant commissioner at Scotland Yard, the Labour frontbench spokesman Chris Bryant and the investigative journalist Brendan Montague. 
 
 Meanwhile it was revealed last night that MPs are to investigate whether parliamentary privileges were breached by Mulcaire. The Commons standards and privileges committee, which has been asked by MPs to investigate the matter, has decided to ask the clerk of the House and outside legal experts to advise on whether phone hacking is a contempt of parliament. 
 
 Miller is waiting for Scotland Yard to reply to a letter asking for an explanation of its failure to warn her, and Bindmans said she would join the legal action if a satisfactory response was not forthcoming. 
 
 During the original investigation in 2006, police told the director of public prosecutions that they would contact all "potential victims". But they failed to inform all those where there was clear evidence of successful hacking until after the Guardian revived the story last year and still have not warned all the owners of the 91 PIN codes found in Mulcaire's possession – Miller was one of them. Police continue to refuse to say how many people they have warned on the grounds that releasing the numbers would risk identifying the individualvictims. ||||| FILE -- Heather Mills clutches a cellphone as she leaves the High Court in London, in this Thursday March 1, 2007 file photo, following a preliminary hearing in her divorce case against Pail McCartney.... (Associated Press) 
 
 Several alleged victims of tabloid phone hacking in Britain will soon file lawsuits against a second newspaper group, Piers Morgan's former employer Trinity Mirror PLC, their lawyer said Friday. 
 
 Mark Lewis said the claims would be filed in "a few weeks," but would not disclose identities of his clients or say precisely when the papers would be lodged at court. 
 
 Lewis represents the family of Milly Dowler, a 13-year-old girl abducted and murdered by a pedophile in 2002. The revelation a month ago that her voicemail messages had been accessed by the News of the World while she was still missing outraged British opinion, and triggered a crisis for Rupert Murdoch's News Corp. 
 
 The phone hacking scandal centers on allegations that journalists eavesdropped on private phone messages, bribed police for information and hacked email accounts. 
 
 So far the crisis has centered on Murdoch's media empire, leading him to shut down the News of the World tabloid and abandon a bid to take over British Sky Broadcasting. Several former executives of the newspaper have been arrested by police investigating the eavesdropping. 
 
 But there have also been allegations of hacking by other newspapers. This week Paul McCartney's ex-wife, Heather Mills, claimed in a BBC interview that she was hacked by a Trinity Mirror journalist in 2001. 
 
 McCartney said Thursday that he planned to contact police over the claim. 
 
 "I will be talking to them about that," McCartney told the U.S. television journalists by videolink from Cincinnati, Ohio. 
 
 The BBC did not identify the journalist cited by Mills, but said it was not Piers Morgan, who was editor of the group's flagship tabloid, the Daily Mirror. between 1995 and 2004. 
 
 Morgan has repeatedly denied ordering anyone to spy on voicemails or knowingly publishing stories obtained through hacking. 
 
 But in an article published by the Daily Mail in 2006, Morgan said that he had been played a tape of a message McCartney had left on Mills' cell phone in the wake of one of their fights. 
 
 "It was heartbreaking," Morgan wrote. "He sounded lonely, miserable and desperate, and even sang 'We Can Work It Out' into the answerphone." 
 
 Questions over how Morgan came to hear the message have led several British lawmakers to call on him to return to the U.K. and explain himself. 
 
 Lawmaker John Whittingdale, chairman of a parliamentary committee that is investigating hacking by the News of the World, said Thursday that Morgan "absolutely should" come to Britain to answer questions. 
 
 Whittingdale said "there is evidence to suggest that other newspapers were involved in phone hacking" _ and that police should investigate. 
 
 Both Trinity Mirror and the publisher of Britain's Daily Mail newspaper, keen to stop the scandal spreading to them, have announced reviews of editorial procedures in the wake of the revelations about the scale of wrongdoing at the News of the World. 
 
 Meanwhile, an activist who hit Murdoch with a shaving foam pie as the mogul testified to British lawmakers last month was appealing Friday against a six-week jail sentence. 
 
 Jonathan May-Bowles was sentenced Tuesday for assaulting the 80-year-old media tycoon as he gave evidence to the House of Commons Culture, Media and Sport Committee. 
 
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 Frazier Moore and Noaki Schwartz in Los Angeles and David Stringer and Raphael G. Satter in London contributed to this report. 
 
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 Jill Lawless can be reached at http://twitter.com/JillLawless
– Sienna Miller is set to join the growing list of outraged public figures taking legal action over phone-hacking by reporters at Britain's News of the World. Lawyers for the star say she plans to add her name to those seeking a review of how the police handled the case and sources at the Rupert-Murdoch owned paper say she's taking steps toward suing it because reporters allegedly listened to her voicemails, the Guardian reports. (For background and opinion on the scandal, click here.) Miller's friends say she changed her number after noticing signs that somebody else was listening to her voicemail, but jailed reporter Glen Mulcaire appears to have obtained her new number as well, although police didn't notify her when they found her PIN code in his possession. A former News of the World reporter who says his editor asked him to hack phones was interviewed by British police last night, the BBC reports.