Hacking scandal: clouds gather over Trinity Mirror as another ex-editor is quizzed by police Britain's second biggest newspaper group, Trinity Mirror, was facing a growing crisis tonight after former Daily Mirror editor Richard Wallace was questioned by police. So far the hacking scandal at the News of the World has cost the biggest newspaper publisher, Rupert Murdoch's News International, at least £260m - more than Trinity Mirror is worth. On Thursday Trinity Mirror was forced to admit to the arrest of former Sunday Mirror editor Tina Weaver, her former deputy Mark Thomas and the serving editor and deputy editor of the Sunday People, James Scott and Nick Buckley. The Metropolitan Police said it was investigating an alleged conspiracy to hack phones at Trinity Mirror's national newspaper group, Mirror Group Newspapers, primarily at the Sunday Mirror and "mainly" during 2003 and 2004. Ms Weaver, who is seven-months pregnant, edited the Sunday Mirror for 11 years until 30 May last year, when she and Mr Wallace were sacked on the spot on the same day during a surprise merger of the daily and Sunday Mirror titles. Indicating that Mr Wallace's questioning was linked to those arrests, Scotland Yard said in a statement: "He was interviewed under caution (not arrested) in connection with the suspected conspiracy to intercept telephone voicemails at Mirror Group Newspapers, which is being investigated by Operation Weeting, and later released." Trinity Mirror's shares slid 20 per cent on the London stock exchange on Thursday, wiping £60m from its value. They were down half a per cent yesterday, approximately £1m. The publisher owns more than 120 newspapers, including the Daily Mirror, Sunday Mirror and Sunday People and scores of regional papers including the Manchester Evening News, Newcastle Chronicle and Western Mail. Until this week the group had emerged largely unscathed from the phone hacking scandal though several former journalists have claimed that hacking took place on its titles. The former Daily Mirror business journalist James Hipwell told the Leveson Inquiry that it was a "bog-standard journalistic tool" during the editorship of Piers Morgan. Mr Morgan, now a CNN chat-show host in America, left the paper over a fake picture scandal in 2004, to be succeeded by Mr Wallace, also a former showbusiness journalist. Mr Morgan has always denied any knowledge of hacking. In his appearance before Lord Justice Leveson last January, Mr Wallace said that hacking "might well have been" taking place while he was Mr Morgan's showbusiness editor. Mr Wallace explained that he had no knowledge of hacking but said it might have been concealed from him. He said in his written statement that he was "not aware of any deliberate transgression of the criminal law at the Daily Mirror that has arisen during my time as editor." Mr Wallace was unavailable for comment tonight.