A pupil who broke into his school to sleep at night finally comes face to face with his former teachers 30 years later to confess - and say thank you - in this week’s episode of Gwesty Aduniad.

In what was the most difficult period of his life, there was one place John Barnett from Tregarth near Bangor considered a safe haven - Ysgol Tryfan, Bangor - and he is eager to thank one of his old teachers from his time there:

“I’m 48; I left school at 16. I don’t get the chance to say thank you to people who helped me;  maybe they don’t notice how much they did to help me. You don’t forget people who helped you. It was these teachers who gave me a chance in life," says John, who’s now a father of three.

Eifion Jones, or ‘Jones Bach’, the school’s maths teacher, realised that John needed the support at the time:

"I didn’t like being home," said John.

"Things weren’t good there - I didn’t feel safe. My stepdad and mam weren’t good to me. I think my mam had problems of her own, but my stepdad added to the problems.

"I didn’t know dad so taid (grandad) was like a father to me. I looked up to Taid like a hero. But Social Services didn’t let me stay with him; I had to go back to foster care. Foster care people were brilliant with me, but I wanted to be with Taid. When I went to the care homes and the foster homes, the teachers helped me.

"I’ve had to grow up young and I missed a lot of my childhood. My grandfather died in 1988, so school became a safe haven for me, I didn’t have to worry there; I was safe there. If something happened, the teachers looked after me; I trusted them."

Things took a turn for the worse for John by the time he was in his early teens, as he had to take food from the school canteen to survive, and took shelter in the building.

“I was sleeping at school. There was a piece of the gate in Tryfan that I could fit through, and I knew that a policeman couldn’t get through that hole."

And now, after all these years, John has the opportunity to thank Eifion Jones for his dedication and support. And unbeknownst to John, Rhys Llwyd, another teacher who was dear to him, joins in the emotional reunion.

You can catch up with the first two episodes of the series on S4C Clic for more stories to warm the heart.

This episode of Gwesty Aduniad is on tomorrow night, Tuesday 20 September, at 9pm on S4C.

English and Welsh subtitles available. and the programme will also be on demand on S4C Clic, iPlayer and other platforms.