Alex, a doting father, smiles sweetly as he strokes the hair of Danny, his sleeping, eight-year-old son: "My baby, wee sweetheart," he coos, before whispering: "Sometimes I wish you were dead."
This is the opening scene to Kid in the Corner, a riveting new three-part Channel 4 drama from Tony Marchant. During the next hour, Alex steadily unravels over Danny's increasingly uncontrollable behaviour. After Danny has attacked his teenage sister with a pair of scissors, Alex screams: "Have you ever seen a boy like that? I've seen a girl like that - in The Exorcist."
It emerges that Danny is suffering from ADHD (Attention Deficit Hyperactivity Disorder), a condition that affects children's ability to concentrate. Marchant has experience of special needs -his teenage son has Asperger's Syndrome, a mild form of autism.
The result is a series which will touch a nerve with all parents. "Alex and Theresa's fears and worries are the fears and worries of all parents writ large," Marchant says. "Kid in the Corner should raise universal issues. Children have never been more judged, and parents have never been more obsessed with their kids' performance. Our children have got to be better than ever, all experts in IT by the age of five."
The drama taps into all sorts of other zeitgeisty issues, too - such as the perceived crisis in fatherhood. "Given a chance, mothers can perform both parents' roles these days. They don't need men," Marchant reckons. "Alex has to confront various things about his role as a father and acknowledge how helpless he is. He's out on the margins emotionally and physically because he realises he may not be a very good father."
Drawing on Marchant's own experiences with a special-needs child, this is drama written from the heart. "We've been through the whole thing, initially thinking it was our parenting that was at fault," he recalls. "Then, when we finally got the diagnosis, we had to persuade everyone that it was a real disorder and not our paranoia about him under-achieving. Then we took the local authority to tribunal over our son's education and lost, so we know what it's like to go through that mill."
Writing Kid in the Corner obviously left Marchant feeling emotionally depleted. "When you write a drama, something is resolved at the end of it. But in my own life, things are a million miles away from being resolved. There is no closure in real life. You can have a happy ending in fiction. But my son is 13, and there's still a long way to go."
The drama is unflinching in its depiction of ADHD; it spares us nothing in its portrayal of how impossible Danny is. Your hackles rise as he lays waste to everything and everybody in his path. What is perhaps most disturbing is the sense that by the end of the first episode we can actually understand why Alex attacks Danny.
Marchant's skill as a writer has always lain in confronting tricky moral dilemmas. He is no exponent of cosy "happy families" drama. Take Me Home tackled adultery, Goodbye Cruel World focused on living with a degenerative disease, and Holding On covered rejecting your family.
The hope is that Kid in the Corner will help raise the profile of this still largely unknown disorder. Rising Scottish star, Douglas Henshall, who plays Alex, declares that: "I'll be happy if one person sitting somewhere says 'Oh my God, that's my wee boy. He must have ADHD.' That would be great."
So where does Marchant go from here? A light-hearted sitcom perhaps? Well, not exactly. He is putting the finishing touches to two heavyweight dramas. First up, he's writing a series for Channel 4 about a former
loan shark who sets up a credit union, and he is also working on No Kissing, a feature film about "a single mother who meets a male escort. It's about the conflict between her responsibilities as a mother and her feelings as a woman."
He pauses before adding with a self-mocking laugh: "It's another feel-good piece of work."