Rochdale Council misled police looking into alleged paedophiles linked to a residential school by withholding a report detailing claims of serious sex abuse there, a former detective says.
Det Supt Bob Huntbach, who is now retired, led inquiries into people linked to Knowl View School in 2000 but says he did not see the 1991 report.
Mr Huntbach says arrests would have been made had he been given it.
The council says it will not comment until it has completed its own inquiry.
Mr Huntbach said he asked Rochdale Council for all the relevant paperwork but claims he was never given the unpublished report, which detailed serious sexual abuse at the school.
"I was not told what I should have known," said Mr Huntbach, who at the time was head of the police domestic violence and child abuse unit in Rochdale.
The BBC showed him the report, written and sent to Rochdale Council in 1991 by a health professional who had visited the school.
It detailed boys as young as eight involved in sexual activity while others had been "forced" to have sex.
The report also stated that men from as far away as Sheffield were travelling to public toilets in Rochdale to have sex with Knowl View boys aged between eight and 13.
Mr Huntbach said he was never shown the report and if he had "it would have been a totally different inquiry with a different amount of staff and a different amount of effort put into it".
"There's an obvious child protection issue and there's obviously criminal issues that needed to be addressed," he said.
The former detective said if he had seen the report he "would have made arrests".
He said: "I'm disappointed that the council didn't engage with us at the time, for the simple reason it was the ideal opportunity and I'm really annoyed as an individual now in retirement thinking I could have done more, I wasn't given the opportunity to do that."
Had he read the report, Mr Huntbach said, he "could have held a lot of people to account".
"It would have been an inquiry taking a different intensity and there would have been a lot more arrests made. As it was, because we had no access to this report, we had very little to speak to people about things, there was nothing there," he added.
In April this year, Greater Manchester Police began a fresh investigation into allegations of abuse and a possible cover-up at Knowl View.
Knowl View School
- Residential school for vulnerable boys opened in 1969 initially as a joint venture between councils in Oldham, Bolton, Rochdale and Lancashire
- Closed in 1995
- Independent review set up by Rochdale Council will examine all decision making relating to Knowl View from the late 1980s until the school's closure
- More than 10 former pupils at the school have come forward as part of Greater Manchester Police's current investigation into abuse
A separate independent inquiry led by Neil Garnham QC is investigating whether Rochdale Council could have done more.
Rochdale Council referred the BBC to the law firm working on the inquiry, which said it was "not appropriate" to comment until the review had been completed.
Mr Huntbach now believes he was misled by Rochdale council.
"There are two ways people can lie to you, by not telling you what you should know or outright lie to you, I think I was not told what I should have known," he said.
The former detective says he also wanted to investigate the late Cyril Smith. Since the former MP for Rochdale's death in 2010, allegations have surfaced that he abused young boys at the school.
Mr Huntbach said he had been aware of allegations against Smith but his enquiries came to nothing.
There was also a wider police investigation at the time, Operation Cleopatra, into allegations relating to care homes across Greater Manchester. It was also looking at documents and it is not clear whether officers on this inquiry saw the 1991 report by the health professional.
Child abuse lawyer Peter Garsden, who represents one man who alleges he was abused in the 1970s at Knowl View, has told the BBC the unpublished reports about the school provide key evidence about what Rochdale council knew at the time.
He said: "In the last 20 years that I've been dealing with children homes investigations I've never seen anything like this, where a report has been done itemising child abuse and very little reaction has resulted from it."
Mr Garsden, who is also president of the Association of Child Abuse Lawyers, added: "There should have been a public inquiry, the children should have been properly interviewed and there should have a police investigation leading to convictions."
He describes "dark forces" operating at the time in Rochdale and says the evidence suggests a paedophile ring was operating for decades in the town.
He said: "This scandal had been going on for many years and paedophiles had been operating there unchecked since at least the 1970s.
"I think there must have been a paedophile ring operating in Knowl View because there were external sex offenders being introduced to the home and that could only have happened by invitation of someone internally."
Detectives investigating the allegations of abuse at Knowl View say they have identified more than 21 suspects, including Cyril Smith. Ten people have said they were abused.
The full scale of the abuse at the school is only now starting to emerge.
Linda who lives in Rochdale and did not want to give her surname said her son, Stephen, was repeatedly beaten by staff at the school.
Stephen would stay at the school from Monday to Friday after it was decided he could not attend a mainstream school.
She said he wasn't sexually abused but faced a brutal regime from the moment he arrived as a nine-year-old.
She said: "His face was smashed into a radiator and caused him to have a nose bleed. They said they would hit him with wet towels, it's ruined my son's life and it's ruined a lot of other lives."
'I feel guilty'
Linda's son, now in his 30s, is no longer able to live an independent life.
"He's still at home with his mum, he's very reliant on family, he won't eat in front of people, he thinks people are watching him," she said.
She said she believed what happened to her son was a "crime against children".
She said she was never made aware of the 1991 report, which warned there would be a "public scandal" if parents found out - despite her son being a pupil there at the time - and had she know about the allegations she would have removed him from the school.
"I would have took him straight out of there, they would have seen smoke from his heels, he wouldn't have been there to be abused no, I still feel guilty about it, I feel as though I owe him, I owe him in some way to make up for what he suffered because I let him go there."
Linda says she wants compensation for the life her son has had since the abuse. The independent inquiry into the role of Rochdale Council is due to report at the end of July.