Yet again another charge of sexual abuse against innocent, vulnerable children has failed to get to court as news of former-Labour MP Greville Janner escaping justice sinks in.

The allegations against Lord Janner are among the most serious sexual offences including repeated buggery of minors.

The pattern of previous revelations against MPs and high-profile individuals is being repeated as evidence emerges of the Crown Prosecution Service (CPS) — in league with very senior police officers — failing to fully investigate the allegations of child sexual abuse.

The Establishment always seems to find excuses for past failures, the result leaves victims who are denied justice.

In 1991, the director of a children’s home in Leicestershire Frank Beck was convicted of child abuse and sentenced to five life terms. During the trial, Janner was accused by Beck of having abused a child and a witness claimed to have been one of Janner’s victims while he was in care.

Janner was unable to comment publicly until after the trial because it would have been in contempt of court but received cross-party support in the House of Commons after Beck’s conviction.

In a Commons statement, delivered on December 2, he said there was “not a shred of truth” in the claims which had been made against him.

Janner was interviewed by the police in 1991 in the first of three investigations which did not lead to a prosecution. During the 1991 interview, accompanied by his solicitor, Janner has been reported as having replied “no comment” to the questions put to him. He and his solicitor, Sir David Napley, were in contact with the barrister George Carman QC in anticipation of a defence brief needing to be prepared if Janner was put on trial.

Further police investigations took place in 2002 and 2006 — documents relating to Janner were not passed to the CPS after the 2002 investigation.

Former Director of Public Prosecutions Lord Macdonald said in April 2014 that the penultimate CPS decision not to prosecute Janner in 2007 was actually made by officials in Leicestershire who did not contact head office in London about the case.

In September 2014, it was reported that Mike Creedon, currently the Chief Constable of Derbyshire Constabulary, claimed that in 1989, while he was serving as a detective sergeant in Leicestershire, senior police chiefs severely limited his enquiries into paedophilia allegations against Janner, despite “credible evidence” that warranted further investigation.

In 2013 and early 2014, Leicestershire Police searched Janner’s home in north London and his offices in the House of Lords in connection with an enquiry linked to historical child abuse allegations. Janner insisted on his innocence. A file of evidence against Janner was sent to the Crown Prosecution Service, but he was not interviewed by the police.

On April 16 2015, the CPS issued a statement indicating that they would not charge Janner owing to his poor health.

During Leicestershire Police’s Operation Enamel more than 20 men were interviewed who claimed Janner had abused them before they were adults. The CPS stated that the case met their evidential test for prosecution and they would have otherwise have prosecuted on 22 counts of indecent assaults and buggery, which are alleged to have occurred between 1969 and 1988.

However, they decided that it failed the public interest test as Janner was diagnosed with Alzeimer’s disease in 2009 and the associated dementia had progressed to a point where he could not engage with the court process and his evidence could not be relied upon.

This meant that a court case could not proceed. Even so Janner continued to claim his generous allowance from the House of Lords.

Alison Saunders, the Director of Public Prosecutions, stated that the decisions made by police and the CPS were wrong. A retired High Court judge, Sir Richard Henriques, has been appointed to carry out an independent investigation of all matters involving the CPS which relate to the case.

Janner was also adamant that former nazis involved in the Holocaust should be brought to trial even though many were in their 90s and suffering from dementia.

On April 16 2015 — a few hours after the CPS decision — the Labour Party suspended Janner.

After the announcement, Leicestershire Police, blamed in the CPS statement for past failures in the investigations into Janner’s activities, said it was considering a request for a judicial review into the CPS decision.

Solicitors representing alleged victims have said that actions for damages against the peer are likely.

Lord Macdonald, the former DPP, told the Today programme on BBC Radio Four on April 18 that a decision over whether to prosecute Janner should have been taken in court by a judge, rather than by the CPS, to remove any doubt that the most recent investigation had been carried out properly.

The Exaro website revealed on the same day that Janner is being investigated as part of Operation Midland, the Metroploitan Police’s enquiry into into the Westminster paedophile ring.

It emerged that Janner had written this month to the House of Lords clerks indicating that he did not wish to cease being an active peer.

John Mann, who was then campaigning to retain his Bassetlaw seat for Labour during the general election campaign, told the Daily Telegraph that all the documents relating to the upper chamber’s contact with Janner should be made public. “I don’t see how you can sign a document relating to membership of the House of Lords if you have dementia,” he said.

• Steven Walker is a Unicef children’s champion.