The Soham murders may never have happened if Humberside Police had dealt appropriately with Ian Huntley, the Inspectorate of Constabulary has said.
Huntley was hired despite assault accusations against him
The report came as Humberside's chief constable, David Westwood, began giving evidence to the Bichard Inquiry.
The inquiry is investigating how Huntley, who murdered 10-year-olds Holly Wells and Jessica Chapman, got a job as a school caretaker.
After his conviction it emerged he had faced a string of assault allegations.
The inquiry is specifically examining how allegations were not shared between Humberside and Cambridgeshire forces.
In its submission to the inquiry HMIC said it was "difficult to believe that a string of eight further allegations of sexual offending would not have at the very least led to collation of a significant and damning intelligence record.
"It is also difficult to believe that Huntley would have been confirmed in the post at Soham....it surely could have led to a very different outcome in this case."
Inspectors found severe shortcomings in both the strategic and practical approaches to intelligence handling more generally within Humberside. There was clear need for a fundamental overhaul of the whole intelligence handling functions within the force.
If Humberside Police had dealt "appropriately" with Huntley his record would have remained on file, it said.
In a written submission to the inquiry, the force's chief constable, David Westwood, admitted vetting checks by Humberside between 1995 and 2003 "cannot be fully relied on".
But he remained uncertain that his force had ever received a vetting request for an intelligence check on Huntley or the surname he was using as an alias, Nixon, from Cambridgeshire Police.
"The totality of the evidence tends to point to the
conclusion that no request for a local intelligence check in respect of either
Huntley or Nixon was actually made of Humberside Police, before, at the time of,
or after his appointment as a school caretaker in Soham," the chief constable said.
He added that he had personally pledged to the parents of Holly and Jessica to learn lessons.
"Huntley did not try very hard to beat the system," he added.
"He got through because basic checks and actions were missed and not due to
major national issues."
The probe, sitting in central London, earlier heard how vetting errors and who was responsible for them would be the focus of the inquiry.
In his opening statement, Counsel to the inquiry James Eadie said Soham College had asked for police checks to be undertaken before employing Huntley.
Counsel for inquiry, James Eadie: Hindsight is a wonderful thing
Those checks had revealed no information about the allegations made in and around Huntley's home town of Grimsby to Humberside Police.
Mr Eadie told the inquiry that when the checks were carried out, in December 2001, two matters had been recorded against Huntley on the child protection register.
One was the allegation of indecent assault on an 11-year-old girl and there was another allegation of unlawful sexual intercourse with a 13-year-old girl.
But the child protection database would not have been searched at the time of the police checks, Mr Eadie added.
Earlier, Mr Eadie said Humberside's child protection database was described by the force itself as "ineffective as a source of information" and "almost
He also said Humberside Police had failed to update Police National Computer records to include Huntley's alias, and so the response to the check in December 2001 would have been "no trace".
Mr Eadie told the inquiry the second main focus of the probe would be on how the systems of checking and vetting could be improved for the future.
Huntley was only charged in relation to one of four allegations of rape but the matter never reached court on the advice of the Crown Prosecution Service.
Mr Eadie said Humberside Police had acted differently from many forces in entering details on the PNC at the point of
charge rather than arrest.
He said: "There was a relatively high barrier to information finding its way
onto the PNC."
Records, including Huntley's, were automatically deleted after three years but still retained on magnetic tapes and CDs.