The UK's top prosecutor today told critics deriding her decision not to prosecute Lord Janner over alleged child sex offences to challenge her in court. Alison Saunders, the Director of Public Prosecutions, said she was 'not afraid' of a legal challenge because she is convinced the Labour peer is not fit to plead because of his dementia. And in her first interview since she announced Lord Janner would not face trial she refused to quit because 'making the right decision is not a resigning issue'. Fighting back: Alison Saunders, the Director of Public Prosecutions, said she was 'not afraid' of a legal challenge over her decision not to charge Lord Janner and said she would not quit . Victims and leading politicians have accused her of 'damaging public confidence' in the justice system with her ruling – even though there was a enough evidence to go ahead with a prosecution. Mrs Saunders admitted herself that three investigations into claims made by 25 alleged victims over 25 years were botched  - but decided it was now too late to charge him. She told the Evening Standard today: '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. I thought long and hard before making it and I'm confident I got it right. My job is not to be populist. 'The medical evidence was very clear. He wouldn't be fit to stand trial, he wouldn't understand the questions, he wouldn't understand the process, he wouldn't be able to understand instructions. 'It's not to make decisions on the basis of what people want. It's about making the right decisions. Sometimes that means it won't be popular but if I'm fulfilling my duties as DPP that's the right thing to do.' Police began investigating Lord Janner, pictured, after allegations of historic child-sex abuse were made but now he is too ill to be put on trial . Last night it emerged Mrs Saunders overruled the advice of two of the country's most senior barristers to allow Lord Janner to avoid a trial. Clare Montgomery QC and child abuse expert Eleanor Laws QC, leading counsel to the investigation, offered advice which could have supported a move to prosecute. In particular, Mrs Laws pointed to overwhelming evidence and corroborating accounts by victims during the two-year police inquiry. But Mrs Saunders decided it was not in the public interest to put Lord Janner in the dock due to his Alzheimer's disease. Campaigners, MPs and victims believe a 'trial of the facts' could have satisfied the need to get to the bottom of the appalling claims against the peer, whatever his mental state. And MailOnline revealed last week that 19 dementia sufferers have been prosecuted for child sex offences and ten were in the past year. The Mail revealed today that Lord Janner signed over the deeds of his £2million home to his children at the height of the police paedophile case against him, it can be revealed. The move puts his luxury apartment potentially out of reach of child abuse victims suing the Labour peer for compensation. The flat, in an exclusive gated community near Hampstead Heath, North London, was transferred free of charge to his two daughters and son in March last year - the same month police raided Janner's Westminster office and three months after they had swooped on his home. In the four years after he was diagnosed with Alzheimer's in 2009, the former Labour MP, 86, has claimed more than £100,000 in parliamentary expenses and allowances. Lord Janner signed over the deeds of his £2 million flat in this complex to his children after the police raid . Even earlier this month, on April 9, he was fit enough to sign a letter saying he wanted to remain in the House of Lords. A week later, the Crown Prosecution Service announced Janner would not be tried over child sex allegations because he was suffering so much from Alzheimer's that he could not even understand any charges against him, let alone answer them. This was despite the fact the CPS ruled there was enough evidence to charge him with 22 sexual offences against children dating from 1969 to 1988. Victims have accused bungling authorities of helping to cover up the crimes of a once powerful man and destroying any hope they had of justice. Child protection campaigners, MPs, police and victims have vowed to challenge the decision in the courts. Last night, two senior Government figures joined the chorus of disapproval and said concerns over the decision were justified. Health Secretary Jeremy Hunt said there was something 'very strange' about the ruling and Health Minister Norman Lamb said the authorities should examine precedents of dementia sufferers being brought to trial. He added that the matter should be brought before a court because Mrs Saunders and the Crown Prosecution Service had made 'heinous errors by failing to bring a prosecution earlier when there was evidence there to do so'. Last seen: Channel 4 News filmed Lord Jenner outside his house in London on July 8 2014, when he was last seen in public . Signed: Dementia sufferer Lord Janner signed a letter on April 9, just a week after he was deemed unfit to stand trial. His signature has been redacted for privacy reasons . Mr Hunt said London Mayor Boris Johnson and Home Secretary Theresa May had been 'right' to express concern at the decision, adding: 'I think we all think that there is something very, very strange here where someone was signing official letters only a matter of weeks ago and is somehow escaping prosecution for something so incredibly serious.' Lord Carlile, a Lib Dem peer and legal expert, said although there was strong evidence Lord Janner had dementia, the decision not to proceed with legal action should be reconsidered. This week, leading politicians from seven parties demanded the decision be reversed. The group, led by Labour's Simon Danczuk, wrote to The Times: 'As long as justice is not seen to be done and the greater public interest is not served, the public will see attempts to investigate establishment figures involved in historic child abuse as a whitewash.' A CPS spokesman confirmed Mrs Laws advised Mrs Saunders to prosecute and that Mrs Montgomery was consulted on an 'ancillary matter'. At least ten men with dementia have been convicted of child sex offences since 2010. Clare Montgomery QC, right and Eleanor Laws QC, left, both recommended Janner should face trial .
Alison Saunders won't quit because 'making the right decision is not a resigning issue'
Head of CPS decided against pressing charges against Lord Janner .
She was persuaded against taking a case by the Labour peer's dementia .
She said: 'I thought long and hard  and I'm confident I got it right'