A prolific sex offender from Northern Ireland, who posed as a teenage boy on Snapchat and Instagram to trap his child victims, has been sentenced to 27 years in prison.

David John Andrews, 55, was told at Downpatrick Crown Court that he would serve a minimum of 13 and a half years, after which parole commissioners would determine when he can be released.

Police have said it is clear his offending, which involved coercing victims into sending him nude photographs, spread across the UK.

During the course of a four-year investigation detectives discovered nearly 10,000 illicit images of children on Andrews’ electronic devices, and approximately 40 usernames that he had used to pose as young boys online.

Andrews, whose address was listed as Maghaberry Prison, had pleaded guilty to 130 charges of sexual abuse, which involve 47 victims, 46 of whom are children.

Most of the offences relate to so-called catfishing, but some relate to the direct abuse of a vulnerable adult woman.

Many of the charges are from 2019 and 2020. Andrews has been on remand for more than four years.

Offences included attempted rape, causing or inciting a child under 13 to engage in sexual activity, sexual communication with a child, blackmail, attempting to pay for sexual services of a child, attempting to arrange or facilitate child prostitution or pornography and making and possessing indecent images of children.

Delivering sentence, Judge Geoffrey Miller KC said he would not detail Andrews’ offending in full as it was “too harrowing and vile to be repeated”.

He said Andrews had posed as a teenage boy on social media and contacted young girls. His youngest victim was eight.

He judge said: “In short form he deceived the children into engaging with him in the mistaken belief he too was a child.

In short form he deceived the children into engaging with him in the mistaken belief he too was a child

“Having done this he then cynically and with clear pre-meditation, used threats to inveigle and coerce them to share images of themselves with him.

“The correspondence instigated by the defendant with each child victim is extremely graphic in content and gives an insight into his depraved thought processes which are deeply troubling.”

The judge added: “He made a conscious decision to create the online persona of a teenage boy with the aim of luring his victims into providing him with sexually explicit images for the sole purpose of satisfying his own sexual urges.

“He then further exploited the victims by distributing the images he had obtained and threatened both they and their friends into providing still more material for his gratification.

“Each time the circle of victims grew and throughout it all he took care to try to cover his tracks.”

Regarding the direct contact offences against the adult victim, the judge said the abuse included Andrews dressing her up and taking explicit photographs, which he sometimes shared with other victims.

The judge said: “The abuse he committed against her over several years displays a depravity that is difficult to comprehend and which is utterly sickening.”

PSNI Detective Chief Inspector Jill Duffie described Andrews as a “heinous child predator”.

She said the investigation into his offending began following a report from Derbyshire Police in 2020 that a number of underage girls had been groomed online by a man believed to be residing in Northern Ireland using the alias of a 13-year-old boy.

She said: “On the same day, detectives from our Public Protection Branch identified the home address of 55-year-old David Andrews in Belfast, arrested him and seized a number of electronic devices for forensic examination.

“Andrews was then interviewed and later charged with a number of child sexual abuse offences, and has been remanded in prison ever since.”

She added: “Following his initial interview with police, it became clear that David Andrews’ offending spanned right across the United Kingdom.

“He used the same behaviour pattern every time to groom young girls via Snapchat and Instagram into believing they were in a relationship with a young boy of a similar age.

“He would then encourage them to send indecent images of themselves, later using these images to threaten, blackmail and abuse them.”

The head of the Public Prosecution Service (PPS) Serious Unit Catherine Kierans said: “Andrews is a dangerous and devious paedophile who abused young children and teenagers online.

“Using the ‘catfish’ method, he pretended to be a teenage boy aged 13 or 14 to target young girls on social media, manipulating and grooming his victims to gain their trust and affection.

“Still pretending to be a young boy, he demanded sexual images and videos from the girls, also sending indecent material to them and recording the abuse.

“When a girl refused to comply or became suspicious of him, he would become abusive or threaten to send her intimate pictures to her friends or share them on the internet.

“Andrews carried through on some of his vile threats to send explicit images to his victim’s contacts. On some occasions, he threatened the girls with violence.”

She added: “Andrews cowardly exploited the vulnerable. The children he targeted online were understandably deceived by the calculating methods of a practiced and callous sex offender.

“His actions caused great fear, distress and trauma to the victims, some of whom bravely raised the alarm, ultimately leading to the outcome today.”