Chasing Dad: A Lifelong Addiction is a quietly stunning look at the horror of heroin

There's no voiceover, just Wood from behind the camera talking to his dad, following him around and bearing witness to his life, which his father says isn't actually a life so much as an existence.

Developed from Wood's graduation project, the film is a quietly stunning look at the horror of heroin, with an intimacy that makes it all the more powerful. The documentary also goes a long way to show that an online-only BBC3 hasn't been watered down.

The camera often focuses silently on the face of Wood's dad, and he looks so shockingly ill, so exhausted with his struggle, it's as though life is slipping away from him as we watch. He's now got all sorts of serious issues with his organs, he tells Wood, including hepatitis C. And his doctor told him that if he doesn't stop drinking, he'll die.

If you know anyone who thinks addiction isn't a disease, show them this film. It dispels any sense that Wood's dad wants to keep living like he is, or that this is the easy option, or that he's simply weak. A cure for addiction like his is incredibly hard to find, and it often fails. But there is some very real hope in this personal tale.

As Wood films his dad, we learn about what it's like surviving in a household of addiction. "What do you think it was like for me growing up?" he asks his dad matter-of-factly from behind the lens. The response is fascinating.

And some of the most frank commentary comes from Wood's sister, who is interviewed at several points during the film. Describing how she used to "hate his guts", she says that now she just pities him for the life he has, for being so ill, for ending up a "lost cause."

But what's even more poignant than hearing this is seeing the behaviour that accompanies his drug abuse. Wood's dad is so used to lying to the world about his habit, so used to denial, to manipulation, that deception is part and parcel of his relationship with his son.

So Wood is never quite sure when his dad is telling the truth, and one of the most interesting moments in the film is when, clearly fed up with the lies, he bluntly asks his dad about this. Over and over again Wood's father breezily tells him he's just popping out for a moment, or just going to have a quick chat with a friend, when he's often scoring a hit.

And this mistrust begs the question of whether this father-son relationship can be rebuilt in any meaningful way. There are some fraught exchanges, some revelations and some really heart-wrenching moments when Phillip Sr really grasps what a colossal impact his addiction has had on his family.

Wood doesn't shy away from getting to the truth, however painful it may be.

Chasing Dad: A Lifelong Addiction is on BBC3 from Sunday 10th April