England - The Roman Catholic Church has ordered a widespread review into its safeguarding children procedures in the South West.
It followed the arrest in March of Christopher Jarvis, 49, who was employed by the Diocese of Plymouth to investigate sex abuse allegations.
Jarvis, of Penrose Road, Plymouth, has been jailed for a year after admitting 12 counts involving indecent images.
A Plymouth Crown Court judge said children who had confided in Jarvis would feel "sullied and let down".
Former social worker Jarvis had worked for the diocese - which covers Cornwall, Devon and Dorset - since 2002, checking on volunteers who wanted to work with children.
The father of four was also authorised to counter-sign applications for Criminal Records Bureau checks and he had access to confidential church files on child abuse cases.
As a member of the Devon and Cornwall Multi-agency Safeguarding Team, he also worked with police officers and social services and had access to private information about vulnerable victims of child abuse.
The court heard that he was arrested after uploading images of pre-pubescent boys to social networking website and was sacked immediately by the diocese.
Police found more than 4,000 child porn images, mainly of boys aged 10 to 12, on his church-supplied computer and a memory stick when they raided his home.
Twelve images were at Level Five, which can include scenes of torture and sadism.
Jarvis, who the court heard claimed he was abused as a child, admitted 12 counts of making, possessing and distributing indecent images.
'Great shock'
Judge Paul Darlow told him: "Children who had confided in you may feel sullied and let down when they find out the person they were confiding in was downloading images in this way.
"You, of all people, were more aware than others of the massive theft of innocence and long-term damage exacted on the children whose images you downloaded for your own sexual gratification."
The diocese said Jarvis had been conducting an investigation into allegations of historic child abuse at a former preparatory boarding school run by monks at Buckfast Abbey before he was arrested.
Ordained priest William Manahan, 80, was jailed for 15 months in 2007 for sexually abusing boys at Buckfast Abbey Preparatory School between 1971 and 1978. The school later closed.
Another monk at the abbey, Paul Couch, was convicted in 2007 of two serious sexual offences and 11 indecent sexual assaults against boys at the school and was jailed for 10 years and nine months.
Jarvis was removed from the investigation after he was arrested and Bishop Christopher Budd ordered the review by the NSPCC.
The NSPCC has already produced a report into case files which Mr Jarvis was involved with over the last three years.
It said "safeguarding concerns have been appropriately responded to and overall, safeguarding practices are sound".
It has also started the second phase, into child protection procedures, policies and training for the protection of children by the Church in the South West.
The diocese said Jarvis had been checked for criminal records and had worked in social services before working for the diocese.
A spokeswoman said the recommendations from phase one were for "very minor" changes, but declined to say what they were.
A diocese spokeswoman said: "The recommendations are not for huge changes.
"What can you do? He had worked for social services."
She said the second phase would look at "how we do things and how we move forward".
She said: "It's extremely sad for everyone."
David Pond, independent chairman of the Plymouth Diocesan Safeguarding Commission, said Jarvis's crimes had been "a great shock to the many people who had placed their trust in him and worked with him to protect vulnerable children and adults".
He added: "This particular incident was not a systemic issue in the Roman Catholic Church.
"It is about an individual who had got himself into a position of trust."