Mirror Group's own journalists to help lawyer investigating phone-hacking A group of disaffected Mirror Group journalists are helping lawyers to prepare new cases that are set to reveal whether phone hacking was employed to deliver some of the publisher's newspapers" biggest scoops of the past decade. The whistleblowing journalists, who include past and current Mirror Group employees, have been assisting the lawyer Mark Lewis. It was announced on Monday night that Mr Lewis is representing four people - including the former England football manager Sven Goran Eriksson - who have issued High Court claims against the publisher of the Daily Mirror and The People newspapers. The claims allege breach of privacy and illegal accessing of mobile-phone voicemails. Following pressure from the company's major shareholders, Trinity Mirror's chief executive, Simon Fox, announced last night that in-house lawyers would investigate the four civil claims. Mr Fox, who took over from Sly Bailey only last month, said it would be "irresponsible" if he did not bring in the company's legal team to "look into the four claims that have attracted this recent attention." However, the limited investigation announced by Mr Fox may have to be widened. It is understood that two further cases against Trinity Mirror titles, one involving a former football manager and the other a businessman, are currently being assessed for potential inclusion in the tranche of claims. Mr Lewis also revealed that since news of the allegations against Mirror titles broke earlier this week, he had been contacted by a number of potentially new claimants. The suggestion that Mirror journalists, who may have kept silent for years over illegal practices, have now turned "rogue" to assist the lawyer at the centre of exposures about phone hacking at the News of the World, will do little to assure Trinity Mirror's major shareholders that the company's current management are in full control of what happens next. When the phone-hacking scandal erupted last July following revelations that the phone of the murdered schoolgirl Milly Dowler had been hacked, Ms Bailey dismissed the need for a review of her group's recent history. She insisted that "all" Mirror journalists operated within the law. A review of practices, conducted by the company's legal manager, Paul Vickers, concluded there was no cause for concern. That information was given to the Leveson Inquiry by Ms Bailey. However, the former Daily Mirror business reporter James Hipwell told Lord Justice Leveson that phone hacking was regularly used by the paper's showbiz team, and that he had been shown "how to hack" by colleagues. Given the new allegations, civil claims and shareholder pressure, Mr Fox has been forced to look beyond the Vickers review, though last night he said that "all our journalists work within the law and the PCC code of practice." It is not yet clear whether the in-house investigation will go as far as the Management & Standards Committee review inside News International, which led to a flood of damaging disclosures about illegal activities at the News of the World. The High Court claims being co-ordinated by Mr Lewis cover the regimes of three Trinity Mirror editors, including Piers Morgan, left, who edited the Daily Mirror between 1995 and 2004.