Seven police officers involved in the failed investigation of widespread child sex abuse in Rochdale will not face any disciplinary action.

Greater Manchester Police (GMP) has admitted the force was focused on tackling robbery and burglary rather than listening to the claims of young, vulnerable victims who were being sexually exploited by older men.

An investigation into the force's handling of the scandal and possible misconduct by officers, led by GMP and supervised by the Independent Police Complaints Commission (IPCC), revealed a number of "significant failures" between 2008 and 2010.

It concludes that the police failed to recognise the "size, gravity and extent" of the abuse and placed too much emphasis on the credibility of the victims, who had complex lives, instead of examining the crimes.

Of the seven officers who were served misconduct notices - including the former divisional chief superintendent, a superintendent, plus two detective chief inspectors, two detective inspectors and one sergeant - one was found to have a "case to answer".

However, the detective inspector has since retired from GMP.

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."

Other failures identified included the "churn" of staff at Rochdale, particularly in the inspecting ranks, which meant that leadership of the issue could not be maintained, and there was little in the way of effective handover.

Some officers did not have adequate public protection training and there were concerns over the sharing of information across agencies that used different IT systems.

Assistant Chief Constable Dawn Copley said the force has taken the "unusual step" of publishing the internal investigation report to show that the case has been "thoroughly investigated, addressed and lessons have been learned".

"I want to start by saying we openly acknowledge that mistakes were made and victims were let down," she said.

"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.

"This report, and the previous serious case review, identified that at the time in 2008-10 there was a strong target-driven focus, predominantly on serious acquisitive crime. At best this was distracting for leaders and influenced the areas that resources were focussed on.

"This has now changed significantly. Child sexual exploitation remains a huge challenge for GMP but it is now one of our top priorities and our understanding and experience of dealing with these types of cases has increased significantly."

She attempted to assure victims that their claims would now be taken seriously following "significant improvements" in the force.

"It is clear that mistakes were made in this investigation," she said.

"We have, and continue to make significant improvements because of the lessons we have learned. We urge victims to come forward knowing that we will take them seriously and thoroughly investigate what has happened to them. People who abuse children will be traced and brought to justice."

Officers involved in the abuse investigation have since 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.

One officer raised her concerns that more than 40 suspects were involved in the "organised, widespread and systematic abuse of vulnerable children" in the area.

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.