A predatory priest's sex crimes were ignored to protect the good name of the Catholic church, a public inquiry found.
Fr Brendan Smyth attacked children "far and wide" at residential homes in Northern Ireland from the 1940s and was convicted of more than 100 offences.
He was allowed a car to roam the country even after he was eventually charged by police in 1991, and over many years his Norbertine religious order and others within the church failed to take determined and vigorous steps to ensure he did not harm more youngsters, the panel found.
A "deliberate decision" was taken to withhold information about Smyth when he was sent to other church dioceses around the world and he was given medical treatment as a "cure" despite continuing to attack minors.
Sir Anthony Hart's report said: "For the Norbertine order and for others outside the order in positions of responsibility in the church, their overriding priority throughout was to protect the good name of the church and at all times to prioritise Fr Smyth's interests, instead of doing what was best for the children abused by him.
"By doing so they were prepared to ignore their responsibilities under the canon law of the church and their obligations under the criminal law as well as their moral responsibilities to the victims of his abuse, thereby allowing him to continue to abuse children far and wide for many decades."
The panel said it was particularly significant that the existing religious law procedures which could have been invoked to bring his crimes to an end were resorted to on only one occasion, during an investigation in the Kilmore area which covers Co Fermanagh and part of the Republic in 1975.
"Even in that instance, steps to have Fr Smyth laicised (defrocked) were not taken."
His youngest victim, according to inquiry witness Fr William Fitzgerald, was aged 28 at the time of the inquiry.
Fr Fitzgerald said: "She is going to be around for another 60 years, maybe, or longer and every day of her life the horrible spectre of that man will be in her mind and what he did."
He said giving her £100 million in compensation would not repair the damage.
He added: "It is unspeakable."
The inquiry said the Norbertines permitted Fr Smyth's ordination despite clear warnings to the contrary.
They failed to warn the bishops of the dioceses to which he was sent in later years, Menevia in Wales, Galloway, Rhode Island and North Dakota, and did not report him to police and social services in Northern Ireland or the Republic, allowing him to continue his abuse.
Instead the order attempted to "cure" him by sending him for medical treatment although it was clear he was continuing to abuse children despite previous attempts.
It also decided not to withdraw his access to a car, enabling him to travel freely and target children in many localities, even after he was charged by police in 1991.
The Sisters of Nazareth and the De La Salle brothers were also found to have failed to report Smyth.
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