Headteachers are hurrying to re-check their staff's references after it emerged that Soham murderer Ian Huntley was employed without his referees being contacted.
The mistake was one of a string of errors uncovered by an inquiry into how he gained the post as caretaker at Soham Village college, even though a number of sexual allegations had been made against him. The inquiry, led by Sir Michael Bichard, ended this week after hearing evidence from teaching unions and the Department for Education and Skills.
Howard Gilbert, head of Soham village college, admitted in an earlier hearing that he had failed to check Ian Huntley's references.
The Secondary Heads Association said it was extremely rare for headteachers to fail to check teachers' references but that many were not so rigorous when employing support staff.
John Dunford, general secretary of SHA, said he expected that heads would now be checking any references they had not verified in the light of the inquiry.
Dr Dunford said that the mistakes which led to Ian Huntley's employment appeared to have been made mainly by the police, who had not informed the school of the previous allegations when his background was checked.
"The fundamental cause of the tragedy was that the system failed," he said.
The teaching unions told the inquiry that the Government should change its guidance so that all school staff, rather than just teachers, receive full "enhanced" background checks.
The National Association of Schoolmasters Union of Women Teachers said it was wrong to believe that teaching assistants, lunchtime supervisors and other support staff needed less rigorous vetting, even if they were not supposed to be alone with pupils.
The NASUWT and Professional Association of Teachers said that the national workforce agreement made it even more vital to expand the full checks because it had broadened the role of teaching assistants.
Although the teaching unions supported increasing the number of in-depth checks, they called for greater caution about the types of background information that are included in enhanced disclosures.
Several cited cases where teachers had missed out on jobs because of malicious and unsubstantiated allegations which had remained on their records.
In a written submission, the NASUWT said that one of its member's records had even contained a complaint which a neighbour had made after they had seen him naked through a window in his own house.
The DfES told the inquiry that it was considering introducing a system which would require supply teachers and others who work with children to carry a "passport" proving they had been vetted.
The Bichard inquiry is expected to publish its findings in May and reconvene six months later to examine how its recommendations have been implemented.