WHAT a ride. I’m standing in Petaluma and can barely believe it. It’s a town in northern California. Just even being here considering the start I had in life is enough. I’ve been through stomach-churning domestic violence and a spell in an unforgiving children’s home. I’ve been mentally scarred and spent most of my youth completely consumed by rage. But I’m here, on the set of a Hollywood movie – and to add to the madness, the entire thing is based on me and my life.

There are cameras whizzing by, booms swinging around and actors getting prepped in their trailers.

Chris ‘Ludacris’ Bridges, one of the stars of the Fast and the Furious film franchise, is playing the man I grew to call dad, Eldridge – who along with his wife Marianna adopted me.

Young rising American actor Shane Graham is playing me.

Fucking hell. It’s almost too much to take in. I really have come full circle. Most of my earliest memories are of being mistreated or beaten by my biological father. I hated that bastard. He’s dead now. I’m having to relive all that pain on set, not only mentally but I’m watching it come to life again – forget magic mushrooms, seeing a film being made about yourself is the most surreal outer body trip you’ll ever experience.

In a strange twist, the director and I settled on the decision that I should play my old man, in a nice little cameo.

Maybe no one else could capture what he was like.

We didn’t subject cinema-goers to a kid being burned alive, something my father did to me.

In the movie, I just throw the boy close to the fire. I couldn’t stomach recreating it fully. It’s one of the few times I guess when the action on screen isn’t a sexed-up version of reality. If I’m being honest, it was the toughest day of my life, but in some ways the most rewarding. There was this massive lift when they finally called cut and my time as that asshole was over. And I’ll admit it. As a youngster, I was an asshole too. I look back in shame at some of the things I did. Can you believe I was embarrassed by the man who adopted me and, along with his wife, offered me a way out?

And here’s the worst part. I was ashamed of his skin colour. I didn’t want anyone to see me with a black guy. I was being given a second chance. So many others never get that. And here was I, about to almost fuck it up because of all the baggage I was carrying – even as a kid. I’d been taught to be racist. If it wasn’t for Eldridge and Marianna’s love, God knows where I’d be. I’d never forget the day they took me to see ET back in 1982. Steven Spielberg’s epic had me transfixed, sitting there in that cinema in Glasgow. It was that scene where the group on their bikes flee the police with ET – I hadn’t a clue what a BMX was. Coming from where I did, it was never on my radar. But I was transfixed. Something inside screamed, ‘this is for me’.

I craved the freedom this little two-wheeled contraption offered.

I was a maniac on the bike. I’d take on all sorts of jumps and stunts. Let’s put it this way, I’ve broken my skull alone four times, and had more concussions than you’ve had hot dinners.

But it wasn’t having a screw loose that was driving me.

It was the pain and negativity from my old life. Now I’m older, I realise riding my BMX was mediation. I was healing my wounds and directing all that rage into a positive outlet. I was good.

But not as natural as the movie portrays – that’s where the screenwriter had a bit of artistic licence.

I wouldn’t call myself a gifted rider. I wasn’t born with supreme talent. But I had determination, due to what I’ve been through and I’ll never take no for an answer – that’s why I made it.

And for me, making it wasn’t about money or fame. It was about happiness. And being able to say, I did it. That moment came for me when I got the call. Asking me to become the global brand manager for Haro Bikes. A lot of the general public might not know Bob Haro. But he’s the godfather and architect of modern BMX riding. He was also the main stuntman in ET. Now, here I was being handed the baton. Bob was the face of BMX. Now, it’s me. Distributing to 80 countries. I sit down regularly with serious big hitters. There are billionaires looking to be part of the sport or sign a deal.

And then, there’s wee Scottish John at the other side of the table – none of them have a clue about where I’ve come from and how my life began.

At Haro we have the biggest budget in the sport to give to the pro riders who I feel deserve it.

Most are far more gifted than I ever was.

In the past few years, my athletes have won gold medals at the X Games and represented their countries in the Olympics.

They’re the best riders in the world. I’m essentially their boss. But I don’t see it that way. I look at it like we’re all Team Haro. And that allows me to make these young riders’ dreams come true. I’m now in control of the BMX company that changed my own life. I’m now the face of the most famous BMX brand on the planet. All I’ve ever had was my passion – and my balls. Now they’ve taken me to the top of my sport. And it’s meant Hollywood called and put my life up on the big screen. I can’t believe I’ve come this far and ended up at a destination so far away and removed from my origins. I’m living the dream, after living a nightmare. Like I said, what a ride.

BURNT flesh. That’s my first memory. Not exactly the normal thing a person remembers from their childhood, and even worse, it was my own.

I began life with my parents – Thomas and Margaret – in Whiteinch. It’s an area in Glasgow, north of the city’s River Clyde, which became a busy hub for shipbuilding during the British Empire’s heyday. Whiteinch itself grew after it became a popular ferry crossing point.Back then I was John Craig. That’s the name I was given when I was born on 16 March 1972 and it’ll become pretty clear why it changed – but let’s put it this way, if I’d stayed John Craig, I wouldn’t be alive now to write this book.Glasgow was going through a tumultuous time and a massive transformation was under way to help rescue thousands of families by setting them up in new housing schemes – all outside the city centre.

They were being shipped out of the old tenement buildings, as the level of deprivation was off the charts with no indoor toilets, a lack of hot water and homes were basically riddled with squalor and unhygienic living conditions.

There was also a famous bin strike in 1975, which saw rubbish piled high, and the rats got so comfortable that the city faced an infestation of the buggers. It got so bad that eventually the army was called in to help resolve the situation.

And we were right in the middle of all that, living in one of these same tenements in what’s known locally as a room and kitchen – two rooms and a toilet. Even calling one of them a kitchen is a stretch, but it did have a sink. At the back of that was a double bed where we all slept huddled together, apart from my dad, who slept in the other room, on his own a lot of the time. So that was our home. We did have pets though, well if you can count the mice that scurried about the place as that.

To be frank, it was a dump and wasn’t much more than a lair for my psycho dad to rule with his violence and bad temper. I think back to living there and what stands out is that it seemed to always be dark and cold.

There were no creature comforts. Nothing to think back on and smile about.

I was the third child to arrive and I was only there for the first three years of my life. My older brother Thomas later told me that he started breaking into bakeries to bring some food home as quite often our cupboards were bare. It was seriously grim. And my only real memory is a horrific one. For a long time I actually wondered if it was a dream. Well, a nightmare would be more appropriate.

But my mother told me in later life that it really did happen. Even now I think back and sometimes say, ‘Surely it didn’t happen like I remember.’ But it did.It happened when I, naive like only a young child can be, was excited to see my dad come home from work – he was a box maker at the shipbuilding firm Yarrow, which manufactured frigates and destroyers for the Royal Navy. Anyway, how was I to know that he’d drunk himself daft on the way back?He was slouched into the chair in our lounge. It was the sort of chair that screamed 1970s. It had that retro mustard felt and those long, narrow wooden arms. If you watch the TV show Mad Men, you’ll see something similar.So he’s sitting there, thinking about God knows what, and I decide to run over. I had barely got my arms around his neck when he saw red. Whether I had startled him or woke him up, I don’t know. I was three for Christ’s sake. But he wanted to make sure I didn’t do it again. He reached over his head, grabbed me around the arms and then hurled me back like a sack of potatoes. I was so small that I flew through the air but as if that wasn’t enough, he had thrown me right in the direction of our two-bar electric fire – which was battling in vain to remove the permanent cold chill of our home. They don’t exist anymore but it was one of the big iron fireplaces, where the bars light up and glow red with heat. And normally you’d have a grille to stop the chance of anyone getting burned or things catching fire.

John Buultjens Is Brand Manager at Official DIG Partners: HARO Bikes