New cases : The decision not to prosecute Lord Janner over historic abuse claims has prompted 30 more alleged victims to come forward . A dossier on Lord Janner is among 114 files on child sex abuse that has vanished from the Home Office , it was revealed today . The 1986 Janner file is mentioned in an investigation into an alleged government cover up but its contents remain a mystery . The Home Office has refused to comment on the dossier , which could potentially conceal the name of a second person , it is alleged . Last year NSPCC boss Peter Wanless led a review of Home Office files from 1979 to 1999 and concluded it would be 'impossible ' to unearth this and the other 113 missing files . According to the Daily Mirror the paper , titled ‘ Greville Janner MP [ redacted ] re evidence in child abuse cases ’ is listed as ‘ not found ’ and ‘ presumed transferred to the MoJ [ Ministry of Justice ] but not located ’ . It came as it emerged up to 30 people have now reportedly told police they were abused by Lord Janner , with more coming forward since it was announced he will not be charged with child sex offences . Publicity surrounding the case has encouraged a new wave of alleged victims to come forward , The Times said last night . The news came as Britain ’ s law chief spoke out publicly for the first time since she ruled the former MP would not face a trial because of his dementia . Yesterday the Director of Public Prosecutions Alison Saunders dared her critics to challenge her in court , and said she is not afraid to see the controversial move tested by a High Court judge . In an appearance on Newsnight she said her decision on Lord Janner was correct when asked if she would not change her mind . She said : 'No . I ’ ve considered the decision very carefully . I mean this wasn ’ t an easy decision to make and I am very aware of the disappointment and frustration that some people will feel around the decision and I feel frustrated that we can not and haven ’ t been able to prosecute it . Scroll down for video . The news came as Alison Saunders , the new Director of Public Prosecutions , has dared her critics to challenge her in court after she decided Lord Janner could not face trial because of his Alzheimer 's . An explosive dossier compiled by MP Geoffrey Dickens is believed to be among 114 files known to have been lost or destroyed by the Home Office . In 1983 the Tory MP for Huddersfield West said he had eight names of 'really important , public figures ' who unless they were arrested he would ‘ expose in Parliament ’ . Based on his descriptions , these are thought to include MPs , civil servants , a diplomat and even a Buckingham Palace official . Some had links to the Paedophile Information Exchange , who wanted sex with children legalised , he said . Dickens handed his '40-page dossier ' to the then Home Secretary Leon Brittan , which set out allegations of a paedophile circle ‘ operating and networking within and around ’ the Westminster elite . Another copy was kept by Mr Dickens ' wife and another was allegedly handed to the then Director of Public Prosecutions , Sir Thomas Hetherington and then the police . All the copies vanished and nothing came of the investigations but now the Dickens dossier is central to allegations that there was a high level cover-up to protect those in power . 'But I have to apply the code for Crown Prosecutors and that means I look at the evidence first : I was satisfied there was a realistic prospect of conviction . 'And then I look at the public interest , which means taking into account Lord Janner ’ s medical condition and his dementia , which is so severe that in my view he would not be able to stand trial . Not just in my view , but more importantly , in the view of the medical experts and we had four medical experts where I was able to take their advice. ’ She also brushed aside calls for her resignation , insisting that ‘ making the right decision is not a resigning issue ’ . In an interview with London ’ s Evening Standard yesterday , the DPP dismissed claims that she was part of an Establishment cover-up . She admitted that she has paid a ‘ heavy price ’ for the decision , but said : ‘ If somebody wants to challenge my decision I ’ m not afraid . 'The proper way to challenge it is through the right to review or a judicial review . I ’ m confident that if they want to do that my decision will stand up. ’ Mrs Saunders said she was right to avoid the ‘ easy option ’ of sending the case to court for a judge to throw out . Last week Leicestershire Police said they were considering a legal challenge , most likely a High Court judicial review . Victims also have the right to review charging decisions , but so far no one has come forward with a request .
Publicity surrounding case has prompted 30 people to contact reporters . Revealed dossier on Lord Janner was among those lost by news Office . blog stew ##art has told critics to challenge her ruling in court . Also said that her decision is ' the right thing ' and does not change .