Social workers were not to blame for failing to discover the child abuse committed by Fred and Rosemary West over a 20-year period.

Last week Rosemary West was found guilty of murdering ten young women, including her own daughter. Her husband Fred killed himself in prison while awaiting trial.

An independent inquiry into the public agencies' involvement in the case - social services, the NSPCC, probation, health, education and the police - concludes the family's avoidance of contact with social services was no surprise. child protection procedures could not have been expected to provide a safety net as the circumstances of the case were unique.

The inquiry, conducted by The Bridge Child Care Consultancy and commissioned by the Gloucestershire area child protection committee, says if health authorities had picked up warning signals, the child protection system could have been activated much earlier. But the social services department was kept in the dark until 1988, a year after the last murder.

'During the early 1970s limited child protection procedures existed, and it was not until the publication of national guidelines in 1988 that guidance was available on the identification of child sexual abuse,' the inquiry says.

The report also suggests that Fred and Rosemary West, having received apparently light, non-custodial sentences when convicted in 1973 of indecent assault, may have confused the way risk to the children was perceived, if it was considered at all.

The report warns that child protection agencies must not reduce their vigilance in dealing with suspicions of abuse. It says the case raises the problem of decision-making when full information is not available. Families which are dangerous for children to live within can convince professionals of their concern, which suppresses the normal fail-safe process.

The inquiry praises the social workers and the police who listened to the evidence from the West children once they were taken into care in 1992, and commends their speed and ability to respond objectively and risk their professional reputations on the basis of what they were being told, including that sister Heather was 'under the patio'.

'The actions of those who listened to the West children have provided a salutary lesson to all professionals working in child protection, whether social workers, teachers, doctors, lawyers, police or the judiciary, not to dismiss lightly the comments of children (however apparently bizarre).'

John Fitzgerald, director of The Bridge Consultancy, said his staff had to hear and read details of systematic torture which could not be published because of court injunctions to protect the West children still in care. 'I hope we will have learned more about sharing information - that's the best way to protect children.'