The headteacher who employed the killer of schoolgirls Holly Wells and Jessica Chapman this week called for a major overhaul of criminal checks on school employees.
David Blunkett, the Home Secretary, announced an independent inquiry into how information on Ian Huntley - including allegations of indecent assault on a 11-year-old and others of rape and under-age sex - was handled by the police.
The former caretaker was brought to the attention of Humberside police 10 times and North East Lincolnshire social services on five occasions.
But he was never convicted or cautioned. Humberside police subsequently deleted information about its contacts with Huntley to comply with data protection laws.
Huntley, 29, was this week found guilty of murdering Holly and Jessica and given two life sentences. His former girlfriend, Maxine Carr, 26, was cleared of assisting him in the deaths but found guilty of conspiring with him to pervert the course of justice, and sentenced to three-and-a-half years in prison. She had worked as a teaching assistant in Holly and Jessica's class at St Andrew's primary school.
Howard Gilbert, head of Soham Village College, said he felt "sickened to the core" that Huntley's background had not been uncovered when the school requested a check.
Both Cambridgeshire and Humberside police failed to pick up on "intelligence" on Huntley. Even if they had, the school might not have received it because chief constables decide whether such information is passed on.
The checks were undertaken before the introduction of the Criminal Records Bureau, but Mr Gilbert fears the same problems could have occurred under the new system which involves two types of check - "enhanced" for teachers and "standard" for other school staff such as caretakers. Standard checks do not involve dropped charges or cautions.
The Government launched a consultation earlier this month on whether other school staff should be eligible for enhanced police checks or disclosures.
Caretakers are specifically mentioned.
But the disclosure of information uncovered through enhanced checks remains at chief constables' discretion.
Mr Gilbert said that had the school known everything earlier, it would have been breaking employment law if it had sacked Huntley.
The school's governors were technically in breach of contract when they sacked Huntley after he was arrested last year for the murders. Mr Gilbert told The TES: "My understanding was if we do a police check and it comes back 'no trace', you feel secure. That has been shaken.
"Had it come back with any of that intelligence, I would have sacked Huntley because I would not have been able to sleep at night. I wouldn't have let him near the school. But I would have been in breach of the law."
He wants heads to be given all relevant information and allowed to come to a decision.
Liberty, the civil rights campaign group, said police intelligence should be available for checks on people working with children, but that they should have the opportunity to rebut any allegations.
Geoff Fisher, head of St Andrew's primary, said: "Some way has got to be found to get round the situation where information cannot be passed on.
Heads can be put in an invidious situation."