From an abusive childhood in Glasgow to an international BMX star, John Buultjens' life is the stuff of movies.

Which is what a Hollywood producer thought when he heard the story.

Now in post-production, The Ride is a biopic of Mr Buultjens' life, from humble beginnings to international fame.

Growing up in Drumchapel, Mr Buultjens suffered years of abuse at the hands of his dad.

"My first childhood memory was in 1975," he told STV News. "I was three-years-old and remember my biological father coming home, and sitting on his little couch.

"I jumped on him because I was excited to see him.

"He grabbed me by the shoulders, threw me over his head and into the fire. My first childhood memory is of the flesh burning off my foot.

"It was an electric fire, but it didn't have a guard, so my foot got caught between the two bars and my sock melted into my foot."

Mr Buultjens recalls that life at home didn't get much better over the years.

"When I was five, in 1977, my dad would just lock me out, he would never let me in the house.

"I was living on the streets, eating out of bins and stuff like that. I would curl up to sleep on the door mat in the stairwell of the flats, or down at the park.

"I would go home but there was just so much violence. It was safer to stay on the streets."

But Mr Buultjens' life changed forever on Christmas Eve, 1979.

"On December 23, my dad was beating my mum up - she was lying in bed and he was just laying into her.

"I grabbed a kitchen knife and ran in to stab him. I didn't get to attack him - he knocked me out.

"The next day, Christmas Eve, I was at school enjoying cake and custard when the police and social workers showed up, took me away and put me in a home."

Mr Buultjens thought he was going to be in care until he was 16, but the home had a foster programme, and in 1982 he was adopted.

"My [adoptive] dad is black - he's from Sri Lanka - and my [adoptive] mum is white. 35 years later, they're my parents still.

"That was the turning point in my life."

After seeing a showing of 80s classic ET, Mr Buultjens became hooked on BMXs.

In 1986, his adoptive dad - a biological scientist - got a job at the University of Dundee, prompting the family to leave Glasgow.

"That's when my BMXing excelled. A guy called Scott Carol, from Broughty Ferry, was the world champion at the time. I met him, met all the skateboarders in Dundee. It was really a crew.

"There was no violence, there was no terrorising people - it was our outlet. It's what made me the man I am today."

After a year spent getting a degree in hotel management, Mr Buultjens emigrated to Australia, where he managed to get a sponsorship from Haro Bikes. He worked part-time jobs in bike shops and picked up bit-parts in television shows such as Neighbours to generate an income.

When an opportunity to become the Global Brand Manager for BMX firm Haro came up, it was too good an offer to turn down.

Mr Buultjens quickly moved to America and became the face of the biggest BMX company in the world.

A chance lunch with director Ali Afshar lead to the filmmaker becoming fascinated in Mr Buultjens' life story.

So 18 months later, in 2015, Mr Buultjens found himself on a film set in northern California with Fast and the Furious star, Chris "Ludacris" Bridges, Sasha Alexander from NCIS and double Emmy-award winner Brian Craig.

In 2017, one of the film producers phoned Mr Buultjens to say he had a new fan - Steven Spielberg.

After being shown a clip for the film, the director fell in love with the story, and even offered them the use of clips from ET.

Mr Buultjens was "blown away" that the megastar knew his story.

Competing for 30 years, the sport has taken him around the world more times than he can remember.

But it took a long time for Mr Buultjens to find peace in his past.

"It took me 23 years to forgive my [birth] mum for having me taken away. I was angry, thinking she was protecting my dad by letting me go.

"When I was 30, I came back to Scotland to see her. I told her 'I forgive you', and she asked what I forgave her for.

"I said 'I've had an amazing life. I thank you for having me, and I forgive you for letting me go. I wouldn't have had this life if you didn't let me go'."

He hopes his film - an upcoming book - will let other young people know that where they are now is not always where they'll end up.

"Living in the present moment, living the now, you can achieve anything.

"You are not your past. That all happened to me but I'm not a victim - I'm a survivor

"I'm proud of who I am and if I can inspire just one other person to let go of their past and not be a victim anymore, it will be worth it."