A series of bureaucratic blunders allowed a teacher to remain free to abuse boys in his care for more than 20 years, an internal council report has revealed.
Hampshire this week released details of an investigation it held after Graham Stride was jailed for seven years in December 2004 on 15 counts of indecent assault against boys aged between 10 and 14.
The county council admitted that poor record-keeping had allowed the 51-year-old from Gosport to continue working as a teacher and move schools, despite repeated complaints about his behaviour.
The full report, which was completed last summer, will not be made public for reasons of confidentiality. Its recommendations were introduced in the autumn to improve child protection.
It called for more explicit sharing and recording of all child protection allegations, including those which did not lead to a conviction, and improved training for headteachers and other staff.
The council decided to reveal the main findings of the report this week and the changes it has introduced to prevent other paedophile teachers slipping through the net.
Stride was jailed for a series of assaults which occurred between 1982 and February 2005 while he was working in schools in Hampshire.
His trial at Portsmouth crown court revealed that when his first victim came forward in 1986, the headteacher did not inform the local authority.
In 1993, Stride was investigated by police for another allegation of child abuse, but the parents allowed the case to be dropped because they did not want their son to suffer the stress of a court appearance.
Although a record of the incident was made by the county council, it was not kept with Stride's file. This meant that subsequently headteachers were not made aware of the allegations.
The county council report said the allegations came at a time when education officials were less aware of the dangers and the techniques used by paedophiles to avoid detection.
In a statement, the council said that the incidents involving Stride had "not always been recorded in the way which would now be expected".
"Those issues regarding Graham Stride's relationship with children which occurred during his working time were dealt with managerially but, because of the state of awareness of child abuse factors at that time, were not recognised as 'grooming' behaviour, and the action taken reflected this,"
the statement said.
"We now know this was all part of Graham Stride's deception and abuse of trust of colleagues, friends, family, the community and, most of all, children."
John Coughlan, director of children's services, defended the authority, saying that the mistakes were down to a "lack of systematic personnel recording".
* Three people convicted of sex offences are working in schools in Northern Ireland, the Government has disclosed. Angela Smith, Northern Ireland minister, said the three were not teaching or deemed a risk and all had committed their offences more than 15 years ago. One had been convicted for sex with a girl who had been "just under age". In the other two cases, the offences were against adult women.
Ruth Kelly, the Education Secretary, admitted last month that 88 sex offenders had been allowed to escape permanent bans from working in schools in England.