The RUC did not treat a complaint from a victim of Jimmy Savile properly, a damning report reveals today.
It is one of eight police forces across the UK that have come under fire for ignoring Savile's abuse victims as it emerged the disgraced presenter could have been stopped as early as 1964.
Inspectors said there is a "distinct possibility" that officers could fail to prevent another Savile-like scandal from happening.
In its 60-page report, Mistakes Were Made, Her Majesty's Inspectorate of Constabulary (HMIC) suggested some victims whose complaints weren't formally recorded were dealt with brusquely.
Eight victims had claimed that they tried unsuccessfully to report crimes – four who approached the Met, and one each who went to police in Cheshire, Merseyside, West Yorkshire and the then RUC, now the PSNI.
Last night a PSNI spokeswoman said: "PSNI have engaged the HMIC review and sought to provide inspectors with as much information as possible.
"We have now received the final report and will give full consideration to its findings and recommendations."
No further details about the allegation made to the RUC are included in the report.
HMIC said: "We have concerns about the extent to which victims may have tried to report their allegations to the police... and, for whatever reason, were not treated as they should have been."
It concluded: "We consider the failure to connect the various allegations was critical to the eventual outcome of the investigations. There was intelligence available of four separate investigations which was never linked together and, because of that failure to 'join the dots', there was a failure to understand the potential depth of Savile's criminality."
Just five allegations and two pieces of intelligence were recorded against Savile during his lifetime, HMIC found. This is in stark contrast to the 450 claims made against the former Top Of The Pops presenter after Operation Yewtree was launched by Metropolitan Police in October.
The earliest record uncovered by HMIC naming Savile in connection with a sexual abuse probe is dated 1964, but officers failed to act on the intelligence received.
A damning report by Met Police and NSPCC said Savile's offending spanned from 1955 to 2009, meaning his reign of abuse could have been cut short by 45 years.
Alan Collins, a solicitor from law firm Pannone who is representing more than 40 of Savile's victims, said further opportunities to investigate Savile were lost.
"There is a definite risk that unless policies and attitudes change, Savile will happen again," he said.
As well as the 1964 Scotland Yard ledger, a record of an anonymous letter to the Met Police in 1998 was found, alleging that Savile was a paedophile.
One man who came forward in 1963 in Cheshire to allege rape against Savile was told to "forget about it" and "move on", HMIC said.
Another went to Vine Street police station in London to report that his girlfriend was assaulted at a recording of Top Of The Pops and was warned that he "could be arrested for making such allegations" and sent away.
HM Inspector of Constabulary Drusilla Sharpling said: "The findings in this report are of deep concern, and clearly there were mistakes in how the police handled the allegations made against Savile during his lifetime."
Considering whether such abuse on a similar scale could happen again, Ms Sharpling said it is neither "enough nor correct to say this couldn't happen now".
The HMIC report said that "the inconsistencies in approach that the forces have taken mean that there is a distinct possibility that such failures could be repeated".
The 1964 intelligence record naming Savile also contains the first known reference to Duncroft School, the children's home in Staines, Surrey.
Police had evidence of sexual abuse involving Duncroft pupils but "lost sight" of this intelligence until last year, HMIC said.
The next occasion Duncroft became known to police, in the context of allegations made against Savile, was in 2007 when Surrey Police commenced their investigation.