© North Wales police/PABenjamin Thomas was the pastor of Criccieth Family church in Gwynedd, north Wales, when he was arrested last year
Ben Thomas, 44, carried out many of his attacks while his victims were sleeping at Christian camps and conferences, Mold crown court in north Wales heard.
Sentencing Thomas for 40 sexual offences involving 33 boys and men, the judge, Timothy Petts, said: "For nearly 30 years, you hid a dark secret, namely that you were a prolific sex abuser."
The vast majority of Thomas's victims were teenage boys and Petts said Thomas used his position as a "respected church leader" to pinpoint victims. The judge said Thomas, who began the sexual abuse when he was 14 or 15, had a "facade of respectability" but was a dangerous offender, and ruled he would be on the sex offender register for life.
Thomas worked for BBC Wales as a presenter on Ffeil, the Welsh language news programme for young people, and as a reporter on Wales Today. He left the BBC in 2005 to preach on the streets of London before returning to Wales in 2008 as the pastor of the Criccieth Family Church in Gwynedd.
His offending came to light when one victim came forward and Thomas was reported to police.
When interviewed by police, Thomas, of Flint, initially answered "no comment", but three weeks later asked to be re-interviewed and confessed to offences against victims aged between 11 and 34 in north Wales, Shropshire, London and Romania.
Many victims were unaware they had been abused until they were traced by police after Thomas's confession, and not all of those he admitted to abusing had been found, the court heard.
Thomas, who has a wife and children, pleaded guilty at an earlier hearing to offences including sexual activity with a child, sexual assaults, attempted sexual assaults, indecent assaults, voyeurism and making indecent videos of children. The court heard he once hid his phone in a wash bag at an outdoor centre to film boys going to the toilet or showering.
On some occasions when his victims woke to find him in their room, he pretended to be sleepwalking, the court heard.
One man who woke as he was being assaulted described his bed shaking and being "extremely frightened", as he believed believing "dark spirits" were attacking him.
In a statement read to the court, another victim described feeling angry, hurt, disgusted, let down and violated. He said: "His face won't leave my thoughts."
A spokesman for the children's charity NSPCC Cymru said: "His offending will have had a profound effect on many of those he abused and it is vital they are able to get all the help they need to move forward with their lives."
R.C.