None of the police officers involved in the investigation of the Rochdale child sex abuse scandal will face misconduct proceedings.
Although one of the seven officers issued with misconduct notices was found to have a case to answer, the detective inspector has since retired from Greater Manchester Police (GMP).
The investigation conducted by the force's professional standards branch, and supervised by the Independent Police Complaints Commission (IPCC), highlights a number of significant failures.
It concludes that the officers placed too much emphasis on the credibility of the victims, and not enough on the crime.
The investigation - titled Operation Span - exposed flaws across all agencies in response to the challenges associated with child sexual exploitation, including a lack of understanding of the complexity of the issue.
Other failures were identified as issues, with information being shared across agencies that used different IT systems, GMP's focus being on addressing serious acquisitive crime, and officers not having the necessary skill set.
It also said the "churn" of staff at Rochdale, particularly in the inspecting ranks, meant that leadership of the issue could not be maintained, and there was little in the way of effective handover.
The investigation identified one detective sergeant who made individual errors in his handling of the investigation, but it found that he had raised concerns about a need for more resources but was not supported by his superiors.
Others who were served notices included the former divisional chief superintendent, a superintendent, two detective chief inspectors, and two detective inspectors.
They all received management action in respect of their performances.
The report was split into two parts, one looking at the handling of the complaints made by two separate children, and the other looking into the wider decision-making by the Rochdale senior leadership team.
The abuse of Child 1 and Child 2 first came to the GMP's attention in 2008, but the Crown Prosecution Service (CPS) decided to take no further action.
But a multi-agency team continued to work with complainants and many others who came forward in 2010.
In April of that year the Public Protection Unit detective inspector made representations to Rochdale Senior Leadership Team for more resources to deal with the growing child exploitation investigation.
In December 2010 GMP's Assistant Chief Constable Terry Sweeney commissioned an internal review into the investigation of sex abuse in Rochdale.
At this point significant investigative resources were made available to support the investigation, and a referral was sent to the IPCC by GMP.
An initial report submitted by GMP was deemed insufficient, and the force was asked to produce another.
Commenting on the report's findings, Assistant Chief Constable Dawn Copley openly acknowledged that mistakes had been made and that victims had been let down.
She continued: "For our part in that we apologise to the victims and we give them our assurance that lessons have been learned, changes have been made and we are determined to use this to continue making improvements."
Ms Copley added that there was a public interest in the report being made public and that it was important to demonstrate lessons had been learnt
Describing the action that had been taken against officers, she said: "A total of seven officers were served with misconduct notices and were formally interviewed about their actions and decision-making, their handling of investigations and victim care. Many more officers were interviewed and all fully co-operated with the investigation.
"The seven officers who were served notices include the former divisional chief superintendent, a superintendent, plus two detective chief inspectors, two detective inspectors and one sergeant.
"All received management action in respect of their performance with the exception of one detective inspector who the investigation found had a case to answer for misconduct. This officer retired prior to the completion of the investigation.
"All officers have been spoken to, the investigation findings shared with them for their personal development and learning and the misconduct and performance issues have been individually addressed."
Ms Copley concluded that significant improvements continued to be made, and urged victims to come forward knowing that their allegations would be taken seriously and thoroughly investigated.
IPCC Commissioner James Dipple-Johnstone said: "There was a failure to recognise the seriousness and scale of what was happening in Rochdale.
"It is appalling that young girls were being exploited and abused and the police did not handle it properly.
"Greater Manchester Police has admitted that the focus in Rochdale was on tackling volume crime such as robbery and burglary. The force simply did not recognise how to respond to child sexual exploitation on this scale."