Lord Janner escaped prosecution three times in 20 years despite credible evidence he sexually abused a string of children in care, it was revealed today.

An independent inquiry by retired High Court judge Sir Richard Henriques has found that the peer, who died in December, should have first been charged with child abuse in 1991.

Police and the Crown Prosecution Service also bungled investigations in 2002 and 2007 when there was a 'realistic prospect' of convicting alleged paedophile Janner.

Sir Richard found officers undermined one of Janner's alleged victims and in another 'remarkable' failure' failed to pass on allegations made by another boy about the MP for Leicester West.

It was only last year, when he was 87 and suffering from severe dementia, that Lord Janner was charged with 22 sex offences but he died at Christmas and devastated victims saw their cases dropped.

Findings: An independent inquiry has found that the peer, who died in December and pictured arriving home with daughter Marion in October, should have first been prosecuted in 1991 for attacking children in care

Pressure: Lord Janner was only charged last year for sex offences dating back 50 years by the CPS, led by Alison Saunders, who admits the CPS and police made historic mistakes not to prosecute Janner

Sir Richard's report, published today, found:

In 1991 there was enough evidence to prosecute Lord Janner for indecent assault and buggery - but police and the CPS bungled the investigation

In 2002, allegations of child abuse made against Lord Janner were not passed on by the police to the CPS

There was also sufficient evidence to prosecute Janner in 2007 for indecent assault and buggery. He should have been arrested, interviewed and had home searched - but nothing happened

CPS AND POLICE REJECTED THREE CHANCES TO PROSECUTE JANNER 1991: A complaint of sexual assaults by one individual who featured in the trial of paedophile care worker Frank Beck. The allegation, in essence, was one of grooming and sexual abuse of the alleged male victim between the ages of 13 and 15. The CPS decided there was insufficient evidence to prosecute. 2002: In an investigation named Operation Magnolia. Lord Janner was the subject of allegations as part of a probe into abuse children's home. The CPS says specific allegations relating to him were not referred to them and claim police chose not to pursue him. 2006: As part of a new sex abuse investigation, Operation Dauntless, an alleged victim made allegations of serious sexual offending around 1981 by three individuals including Lord Janner. The CPS decision in 2007 was again that there was insufficient evidence to prosecute. Advertisement

Sir Richard was asked to evaluate the handling of allegations of child abuse aimed at Janner, which were dismissed three times in the past 25 years.

The claims against him first surfaced during an investigation into Frank Beck, a manager of Leicester children's homes who died in jail after being convicted of abusing boys in his care in 1991.

A former resident of one home alleged he had a two-year sexual relationship with the MP when he was a teenager in the 1970s.

He claimed that he was buggered against his will on five occasions by Janner in various hotels.

The alleged victim later caused controversy when he aired the allegations in public while giving evidence at Beck's trial in 1991.

MPs on all sides rallied around Lord Janner when he told the House of Commons the claims did not contain a 'shred of truth'.

In his report Sir Richard slammed the CPS and police officers for failing to pursue Janner at the time.

He said: 'I am satisfied that, in 1991, there was a sufficiency of evidence for a prosecution to be commenced against Janner for offences of indecent assault and buggery.

'The police investigation was incomplete and inadequate in 1991 and police officers failed to carry out enquiries advised by the CPS.'

The CPS clerk who managed the 1991 case file admitted there was 'reticence on the part of the police' to fully probe whether the politician abused an underage boy hotels and at his home.

As part of an 'inadequate' investigation police also ignored letters on Parliamentary paper between Janner and the boy found Beck's house.

Sir Richard said they did not prove Janner was a child abuser but in them he sent 'his love' to the child, said he missed him and urged him to keep writing.

Several witnesses placed the peer with the then 14-year-old at the Holiday Inn in Leicester, where the boy said he was abused, yet police and the CPS concluded there was not enough evidence.

On one occasion the boy stole cash from Janner's wallet in an Aylesbury hotel while the MP admitted he was in the shower, suggesting they were sharing a bedroom.

Officers investigating notorious paedophile Frank Beck, who was jailed for life for abusing children, accepted Janner's claims he did now know him.

But alleged victims and others in care said that Janner was a regular in the children's homes Beck ran in Leicestershire and Beck referred to the peer as one alleged victim's 'pimp'.

Probes: Greville Janner, left in 1974, served as an MP for decades and was investigated in 1991, 2002 and 2007. Janner was mentioned during the trial of paediophile Frank Beck, right, who died in jai

Sir Richard found only 'extremely limited' inquiries were made at the children's homes where he lived.

The alleged victim even went to a wedding with the peer's family, and it was only two decades later in 2014 that a subsequent police investigation found there was film footage of Complainant One at the event.

The report found: 'I have concluded that the decision not to charge Janner in 1991 was wrong and that there was enough evidence against Janner, on December 4 1991, to provide a realistic prospect of conviction.'

Evidence available at the time included the alleged victim's statements, as well as accounts from staff and residents at care homes and information from a social worker and social services records.

The identity of the prosecutor who told police there was not enough evidence is not known.

Allegations: Veteran peer Lord Janner (pictured in 2002) repeatedly denied claims he abused young boys at care homes but this was never tested in court

A second alleged victim came forward in April 2000 when police in Leicester were investigating abuse in children's homes.

He made a statement claiming he had been seriously sexually abused by Lord Janner, but this was not passed to the CPS in a file submitted in 2002, and no further action was taken.

The report said Janner should have faced prosecution for two counts of buggery, one count of indecent assault and one count of gross indecency, as well as the 1991 claims, at this stage.

Sir Richard said in 2002, when a fresh complaint was made against Janner, 'the failure to forward (the alleged victim's) statement to the CPS for charging advice is remarkable and merits investigation by the Independent Police Complaints Commission.

'Had the statement been forwarded to the CPS, there was, in my judgement, a sufficiency of evidence to commence a prosecution against Janner, in 2002 on two victims.

In 2007, a reviewing lawyer at the CPS, who had also advised in 1991 and 2002, said problems with the credibility of a third alleged victim, Complainant 3, again meant the peer could not be prosecuted.

He told police he was abused by the Janner and Frank Beck pair as a child and said the MP had on one occasion: 'patted Beck on the back and said: "Well done, you groomed him well" - but Janner was never charged.

Sir Richard said the third complaint, in 2007, was rejected by a lawyer in Leicester but he said he disagreed with the decision.

There was also an eight-month delay between the police file being submitted and the charging decision being made.

Sir Richard said: 'In my opinion there was sufficient evidence to provide a realistic prospect of conviction in 2007, and Janner should have been arrested and interviewed and his home searched.

Director of Public Prosecutions Alison Saunders was at the centre of a storm of controversy last year after originally deciding Lord Janner, who had dementia, should not be charged because of his ill health.

That decision was overturned by an independent review last year. A special hearing known as a trial of the facts had been scheduled for this year, but last week the criminal case was formally dropped following Lord Janner's death.

Mrs Saunders said today: 'The inquiry's findings that mistakes were made confirms my view that failings in the past by prosecutors and police meant that proceedings were not brought.

'It is a matter of sincere regret that on three occasions, opportunities to put the allegations against Lord Janner before a jury were not taken.

'It is important that we understand the steps which led to these decisions not to prosecute, and ensure that no such mistakes can be made again.'

Alleged sex abuse victims of the late Lord Janner were devastated last week after the criminal case against him was dropped.

He had been charged with 22 sexual offences dating back to the 1960s against nine alleged victims, who were mostly under 16 at the time.

But legal proceedings were left in limbo when the 87-year-old Labour peer died on December 19, days after he was found unfit to stand trial. He had been suffering from dementia.

Announcing the decision not to press ahead with a trial of facts scheduled for April, prosecutor Richard Whittam QC told the Old Bailey that more charges had been due to be brought.