Executive director Maeve Lewis said: “We are extremely worried that dangerous sex offenders may be continuing to abuse children even though we have brought them to the attention of Tusla.”

In the charity’s annual report for 2016, One in Four says that most of the child protection notifications made to Tusla are returned as “unfounded”.

In 2016 it made 91 child protection notifications to Tusla, all of which were based on very serious allegations made by the charity’s clients in relation to experiences of child sexual abuse.

Of these notifications, 12 were accompanied by full statements to social care workers, of which eight were not investigated or deemed “unfounded”. Three of the allegations are ongoing and one case has come back as “founded”.

One in Four said that 79 clients of the 91 cases chose not to meet with a social care worker and it was, therefore, difficult for Tusla to investigate an allegation without a full statement.

Ms Lewis stated that Tusla needs far greater resources in order to deal with the volume of notifications because perpetrators of sexual abuse continue to abuse until they are caught.

“Our clients are adults who were sexually abused as children, but we know that sex offenders generally continue to abuse until they are caught. The father who abused his children may now be abusing his grandchildren; the teacher who abused one generation may now be abusing the next,” said Ms Lewis.

“Tusla has made strides in putting in place retrospective teams across the country, but our figures speak for themselves. From all these very substantial allegations, only one offender is now being monitored. We believe that Tusla child protection teams need much greater resourcing to deal with the volume of notifications.”

The annual report includes figures on the number of people who received help from the charity last year.

In 2016, One in Four provided 2,563 therapy hours to 143 adult survivors of child sexual abuse and 53 family members.

Separate to counselling work, the charity’s advocacy officers supported 646 people to engage with the criminal justice system as well as to make child protection notifications.

In relation to the profile of its clients, 40% were male, which, according to One in Four, “challenges the idea that boys are not sexually abused”.

In terms of the survivors’ relationship to the perpetrator of the abuse, 46% of One in Four’s counselling clients were abused in their own families, 11% in the Catholic Church, 10% were abused by neighbours, and 19% by strangers.

Other statistics show that 9% of counselling clients were abused by more than one person.

Ms Lewis said that the charity’s waiting list is currently closed, which, because a large number of its clients attempt suicide, is of “huge concern”.

“In 2016 we met 94 new clients and 43 of these had attempted suicide at some point in their lives. It is a huge concern that we cannot respond immediately to people who ask for our help,” said Ms Lewis.