Britain's most senior prosecutor was tonight urged to resign after performing an embarrassing U-turn over the decision not to make Labour peer Lord Janner stand trial.

Alison Saunders said just months ago that the 86-year-old was too ill to be prosecuted for child sex offences allegedly spanning 30 years - even though there was 'sufficient evidence to prosecute'.

But yesterday, an independent review into the decision recommended that the original ruling be overturned and the case against the former MP heard in court.

However, the review did not dispute Lord Janner, who has been suspended from the Labour party, will 'inevitably be found unfit to plead' by a judge - raising concerns that he will still avoid a full trial.

Simon Danczuk, the Labour MP for Rochdale who has campaigned for the case to be heard in court, said Mrs Saunders was responsible for a 'catalogue of errors' - and was 'not fit to do the job'.

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Proceedings: Alison Saunders (left) said just months ago that Lord Janner (right) was too ill to be prosecuted for child sex offences allegedly spanning 30 years - even though there was 'sufficient evidence to prosecute'.

If a judge rules Lord Janner is not fit enough to plead or give evidence, the most likely outcome is 'an absolute discharge, which is neither punishment nor conviction', the Crown Prosecution Service said.

Lord Janner, who was the MP for Leicester West for 27 years, denies any wrongdoing and his family says the peer 'is entirely innocent' of any wrongdoing.

But prosecutors believe there is enough evidence to prosecute him and have formally charged him with 22 counts of sexual abuse - including alleged indecent assaults on children under the age of 16.

It comes after a review of the case by David Perry QC concluded that it was in the public interest to bring proceedings before a criminal court.

In April, Director for Public Prosecutions Mrs Saunders controversially ruled that despite there being 'sufficient evidence to prosecute' Lord Janner it was not in the public interest to prosecute.

It was stated that this was because there was 'undisputed medical evidence that Greville Janner was not fit to stand trial'. She said this meant there could not be a full criminal trial.

Mrs Saunders yesterday insisted that she would have brought a prosecution if Lord Janner was not so unwell. However, in May, six of his alleged victims formally requested that the decision be reviewed.

Campaigner: MP Simon Danczuk said that Mrs Saunders was responsible for a 'catalogue of errors'

The review, published yesterday, concluded that Mrs Saunders was wrong to rule out a prosecution. Independent QC David Perry said it was in the public interest to bring proceedings before a court.

Mrs Saunders is now facing a fight to stay in her job, with victims groups and MPs calling for her to resign. Yesterday, she defiantly dismissed calls for her to stand down over her original decision.

She said: 'I don't think this is a decision I should resign over. It is one I took very carefully and with the victims at the heart of that.'

But Simon Danczuk, the Labour MP for Rochdale who has campaigned for the case to be heard in court, said that Mrs Saunders was responsible for a 'catalogue of errors'.

However, Mr Danczuk said: 'I think she should resign for a number of reasons. She has made a number of bad judgments and she is just not fit to do the job.

'She ignored her advisers, took a long time to make the decision, then announced it when parliament was not sitting although there was significant public interest.

'Most important of all, it was a serious mistake because she failed to understand both the mood of the public and the emotional distress she was causing to the alleged victims.

'We cannot have somebody leading the Crown Prosecution Service who is cold and dispassionate towards alleged victims.'

Specialist abuse lawyer Liz Dux, who represents many of Janner's alleged victims, said she was 'delighted' by the decision yesterday morning.

Spotted: Lord Janner, the 86-year-old, was last seen in public walking outside his house in London last July

She said: 'Our clients have waited long enough for their very serious allegations to be brought before a court.

'They have felt deeply frustrated by the criminal justice system. However, this decision has given them more hope of finally establishing the truth.

'It may be long overdue, but we will now look to a criminal court to examine the case and make a finding of fact. It is now absolutely vital that nothing is done that could prejudice a fair trial.'

Alison Saunders has brought the criminal justice system into disrepute Labour MP Simon Danczuk

Peter Wanless, NSPCC chief executive, also welcomed the decision. He said: 'It takes incredible courage for victims to come forward and they need to have confidence that those in positions of power and privilege are not above the law, or they will not muster the courage.

'Momentum is building in our society so that victims speak up believing justice can be achieved. The original decision not to prosecute was a setback - thankfully a temporary one.'

The first hearing will take place at Westminster Magistrates' Court on August 7.

Mrs Saunders yesterday morning insisted that it was a matter of 'real regret' that prosecutions weren't brought by the police and CPS in the past and defended her record tackling child abuse.

She said: 'I have always said that in my view this was an extremely difficult and borderline case because of the strong arguments on both sides.

Royalty: Lord Janner watches on Queen Elizabeth II (left) meets a guest at St James's Palace in October 2003

'I have also always emphasised my concern for the complainants in this case. I understood their need to be heard, which is why I contacted Justice Goddard to ensure that they could give evidence as part of the public inquiry.

'However, the review has concluded that this forum, albeit a public one, cannot substitute for the adjudication of the courts. I accept the outcome of the review and will now be bringing this prosecution to allow for that adjudication to happen.

I don't think this is a decision I should resign over Alison Saunders, Director of Public Prosecutions

The Attorney General Jeremy Wright also defended Mrs Saunders amid calls for her to step down.

Mr Wright said: 'I believe strongly in a system where decisions to prosecute are taken by independent prosecutors and not by politicians.

'I am confident of the independence and the integrity of the Director of Public Prosecutions, Alison Saunders, in making the difficult judgements the job of a prosecutor involves.

'It is right that we now have a victim's right to review those judgements, which Alison helped to bring in, and which has operated as it was designed to in this case.

'Since Alison Saunders has been DPP, the CPS has prosecuted and convicted more child sex offenders than ever before.'

CRITICAL REPORT WILL NOW BE DELAYED UNTIL AFTER THE TRIAL Put back: The publication of a critical report highlighting how police and prosecutors failed to bring Lord Janner to justice has been postponed The publication of a critical report highlighting how police and prosecutors failed to bring Lord Janner to justice has been postponed. A draft review by Sir Richard Henriques found the way Leicestershire Police dealt with allegations against the peer were ‘unsatisfactory’. And the retired High Court judge said decisions by prosecutors not to put Janner in the dock were simply ‘wrong’. But the Crown Prosecution Service said the full review will not be published until proceedings against Janner, 86, were complete. Alison Saunders said the preliminary findings confirmed her fears that the wrong choices were made. ‘It is a matter of real regret that prosecutions weren’t brought by the police and CPS in the past,’ she said. Sir Richard examined multiple failings by Leicestershire Police and prosecutors when victims came forward in 1991, 2002 and 2006. In the first case, an alleged victim aged between 13 and 15 contacted police in 1991. A case file was passed to prosecutors who advised police there was ‘insufficient evidence’ and police took no further action. The second set of allegations were made against Janner in 2002. Although prosecutors examined the actions of other individuals and ruled they should not face charges, they were not alerted to Janner’s alleged involvement by police. In 2006, an individual came forward with claims of serious sexual offences by Janner and two others. Local prosecutors ruled there was not enough evidence to bring a court case in 2007 but did not alert their London headquarters. The then director of public prosecutions Sir Ken Macdonald, who said he was not aware of the case, has already labelled this a ‘grave failure’. Advertisement