Independent report into investigations of peer due out in days as critics say his death should not have affected trial of facts

Alleged victims of sexual abuse by Greville Janner have hit out at the decision to drop court proceedings against the late peer, saying it amounted to “an establishment cover-up from day one”.

The case against the former Labour MP, who was charged with 22 sexual offences dating back to the 1960s against nine boys and men, was set to be heard in a trial of the facts from which Lord Janner would be absent because of his dementia.

After his death last month, prosecutors suggested the trial could go ahead posthumously. But on Friday the prosecutor Richard Whittam QC told the trial judge, Mr Justice Openshaw, that the crown would not go ahead with the proceedings planned for the Old Bailey in April.

A long-awaited independent report into why it took decades to bring Lord Janner to court to face child sex abuse charges is due to be published this coming week, sources have told the Guardian.

The Crown Prosecution Service and Leicestershire police are expected to face severe criticisms from retired judge Richard Henriques for mishandling investigations into the late peer in 1991, 2002 and 2007.

One solicitor who represents alleged Janner victims said the report could shed light upon claims that the police were pressured by politicians to drop their previous inquiries.

One alleged victim said on Friday that the decision to drop proceedings against the former MP would increase suspicion of “an establishment cover-up from day one” that stopped Janner from appearing before the courts.

The 54-year-old man, who has claimed he was abused repeatedly in a children’s home by Janner over several years, said: “I am really disappointed. He was already deemed unfit to stand trial and wasn’t going to be in court anyway, so his death shouldn’t have made a difference.

“The fact that he kicked the bucket should not have mattered. For once, they should have thought about the victims and let us go to court and let the court decide if we were telling the truth.”

The alleged victim’s case mirrors that of others who have said they were based in children’s homes in Leicestershire when Janner, the then MP for Leicester West, was introduced to them.

The man’s account and those of other alleged victims were first given to the police in 1991 and were raised again with detectives in 2005. After a further inquiry in 2014, Leicestershire police said there was enough evidence to pursue a legal case against Janner.

The alleged victim, a labourer, said the decision would leave many feeling abandoned by the justice system.

“I was going to go to court and tell them what happened,” he said. “I thought I was finally going to get some closure. Think what us, the victims, have been through. We were abused by a powerful man. When we plucked up courage to speak to the police, they didn’t believe us; decades later, we finally get near to a court and, somehow, he gets away with it and cheats the court because he dies.”

The BBC, which has interviewed dozens of men and women who lived in children’s homes in Leicestershire in the 70s and 80s, reported on Friday that 12 former residents had claimed they were abused by Janner.

The broadcaster spoke to council officials, social workers, police officers and journalists involved in investigating the case of Frank Beck, a notorious care home manager who was eventually convicted of child abuse.

The BBC reported that lawyers were now representing at least 20 men and one woman, including the 12 residents of children’s homes, who say the former MP abused them and that police had said they had information from 25 alleged victims.

Liz Dux, of Slater and Gordon, who represents a number of Janner’s alleged victims, said the claims against the former Labour MP were of the most “serious nature”.

“My clients are absolutely devastated that they won’t give their evidence in a criminal court,” she said. “They totally understand the reasons why, but that doesn’t make up for the real travesty – that many gave their statements decades ago and have been denied justice through a failure to prosecute earlier when Janner was alive and well, and that’s something they can’t get over.

“The next stage is the only opportunity for them to have their evidence heard, by the independent inquiry into child sexual abuse led by Judge Goddard. We’re hoping there will be an announcement by the Goddard inquiry shortly.

“I hope they prioritise the Lord Janner case and that they will hear my client in person and make findings of facts so there are judicial findings made and then made public.

“What is very disappointing is there was a painstaking inquiry by Leicestershire police since 2013 with a lot of other witnesses’ evidence, who weren’t victims but who were there to corroborate what victims were alleging. That evidence won’t be heard either.”

At the time of Janner’s death on 19 December, the prosecution had an application pending to introduce a second tranche of charges, which covered additional victims.

Janner was subject to three police investigations between 1991 and 2007. The CPS had, in those inquiries, decided there was insufficient evidence to charge Janner as a result of two of the investigations while the police did not submit a file to prosecutors on the third one.

In April last year, the director of public prosecutions, Alison Saunders, said the evidential test was passed, but that “mistakes in the decision-making” were made by Leicestershire police in 2002 and the CPS in 1991 and 2007.

The report by Henriques into the failures of previous inquiries last spring, which is expected to be released within days, will “go further” in its criticisms, sources say.

The report’s findings will be closely examined by lawyers representing at least 20 alleged victims of Janner who are already pursuing civil proceedings against the peer’s estate.

Some alleged victims have voiced suspicions that ministers and senior politicians from the Conservative party and Labour may have interfered in police inquiries.

Peter Garsden, head of QualitySolicitors Abney Garsden, said: “I hope the Henriques review will elaborate upon whether the police were put under pressure by the government not to prosecute Janner, something which has long been rumoured.

“The victims will await its publication with anticipation of it uncovering any cover-up which took place in the past. This has led to them being denied justice at a time when Janner was not lacking in capacity.”

Another legal source claimed that the report could also lead to civil cases against the police or the CPS.