An aspiring barrister has been jailed for 10 years after recording more than 150 children carrying out sex acts he told them to perform.

Owain Thomas, 29, from south Wales, targeted children between the ages of nine and 16 on the internet, paying some with online game currency to encourage them to co-operate with his demands to perform indecent acts.

Thomas, an Aberystwyth University law graduate, used Facebook and online gaming rooms to meet young boys and girls, sometimes posing as a child himself.

Merthyr crown court heard Thomas used “persistent and sophisticated techniques” including disguising his voice and using different accents during on-camera chats with his victims, where he repeatedly exposed himself.

He also purported to be some of his older victims when showing explicit images taken of them to younger children.

He was caught on 17 November last year after he approached two eight-year-old boys in his car in Ferndale, Rhondda Cynon Taf, and asked them to show him their penises. The boys refused and he showed them sexual images from his phone as he drove past.

The boys complained to their parents, and he was tracked to his home in Pontypridd, where a crying Thomas told police: “I need help. I know I need help. I can’t go to prison, I won’t cope in there.”

Police found a “vast amount” of child sex abuse images on his computer, with more than 150 child victims from the UK and the US. Police say 146 have been identified.

He later pleaded guilty to 158 sex offences, including causing or inciting children to engage in sexual activity and distributing indecent images.

A pre-sentence report read in court said Thomas would target children he deemed vulnerable after meeting them online, and would take away attention and friendship if they did not comply with his demands.

The recorder of Merthyr Tydfil, Judge Richard Twomlow, said Thomas was a dangerous offender. He told him: “I have no doubt you pose a significant risk of serious harm to members of the public.

“You were about to move to actual contact as opposed to contact over the internet.”

Twomlow added: “This may have been through a screen but this was a very real experience for your victims. You went as far as you could persuade these children to go. You had multiple identities including pretending to be a nine-year-old girl.

“A recurring theme in this case is your persistence. If you couldn’t convince them, you would return and try again.

“Because of the sheer volume and scale of your offences I have no doubt that you are a significant risk to the public and pose a real risk. You are a dangerous offender.”

Thomas was jailed for 10 years, with an extended sentence meaning he will serve at least two-thirds of his term behind bars until a parole board will consider releasing him. Following his release he will spend five years on licence.

Speaking outside court, South Wales police gave some insight into the delicate task of tracing victims and explaining to their parents or carers what had happened.

DI Lianne Rees said: “To tell any parent that their child has been a victim of a sexual predator was not easy.

“What was so alarming was the high percentage of parents who had no clue whatsoever what their children were doing online, and that should be a warning for others.”

His victims were from Wales, England, Northern Ireland and the US.

Rees said: “There are predators out there who are very good at manipulating – children are vulnerable and should all be safeguarded effectively and parents have a big role to play in that.

“Being a technophobe can no longer be an excuse, as there are many websites out there which give advice and information to parents on how to keep children safe online.”