Just 12 members of a notoriously abusive Catholic order of priests have been convicted of crimes since 1975, a watchdog has revealed.
The Christian Brothers, one of the largest religious and teaching orders, face allegations that 325 priests who worked in schools in Ireland over the last 38 years attacked youngsters.
An audit by the Catholic Church's own watchdog - the National Board for the Safeguarding of Children - found that the order's initial response to abuse was inadequate and not systematic.
There were 870 complaints of abuse over four decades, all of which have been reported to authorities, but only 50 of the accused priests are still alive.
The audit was one of eight released in the latest tranche of oversight inspections into Irish dioceses and religious orders.
The Kiltegan Fathers, also known as the St Patrick's Missionary Society - which has sent hundreds of priests to Africa and other parts of the developing world, was criticised for inadequate recording of allegations, incidents and suspicions.
The watchdog said abuse by missionaries outside Ireland was not always met with appropriate and robust action and that children abused overseas by priests were not given the same level of priority as those at home.
Fifty allegations were made about members of the Kiltegan order in the 38-year period since 1975.
"Accused priests were afforded too much tolerance and so found it too easy to avoid being held accountable for their actions," the report said.
"It also appeared to the reviewers that the identification of abuse of a child on the missions did not always evoke the actions that evidence an empathic response to the experiences of victims."
In one case from Kenya, reports of a priest sexually abusing a young boy first emerged in 1966, but were not acted on for 31 years. It is thought the priest had 50 victims.
The allegations involved 14 individuals - nine of whom were still alive when the review was taking place - while five have left the order. Only one member of the order has been convicted of child abuse.
Kiltegan society leader Father Seamus O'Neill apologised unreservedly to victims of abuse and their families.
"We acknowledge the courage of the victims who have come forward to report abuse to our Society and to the civil authorities.," he said.
"Nothing can undo the horrendous effects of the abuse they suffered at the hands of those who should have been their protectors. The members of our Society deeply regret this betrayal of trust."
The review described the levels of abuse perpetrated by Kiltegan Fathers as relatively high.
While improvements have been made in child protection standards, the order was found to have completely failed in requirements for a written plan on what should be done to keep children safe.
The latest reviews by the oversight body is the largest released in one go and they scrutinise current practice in two religious orders and six dioceses and the handling of all allegations received since January 1975.
The Christian Brothers first made a public apology in 1998.
The level of abuse from members of the order was described as substantial.
Members of the congregation, which based its teaching system around rules, compliance and strict adherence, taught in some of the order's 105 schools in Ireland, 10 in Northern Ireland and 95 in the Republic.
The audit warned: "The number of convictions by the courts, compared to the numbers accused of child abuse, is significantly small."
In the 66 years between 1931 and 1997, the Christian Brothers received 92 allegations of abuse but in the subsequent 15 years, from 1998 to this year, they received 794 allegations.
Since internal reviews in 2007 and 2009, the safeguarding board said it is now satisfied that reports are made promptly.
The Christian Brothers said they accepted that a safeguarding deficit existed in the past.
"We want to learn from the mistakes of the past and to create a safe environment for all children and young adults," it said.