Jason, eight, staggers around the classroom, pretending to be drunk. He buries "dead" toys in a sand tray or locks them up in a prison of his making. As punches and kicks are unleashed on a settee, Jason's face is taut and impenetrable.
Each moment is captured on camera by filmmaker Matt Pinder, who spent a year observing Jason and two other Glasgow primary children. All had profound difficulties fitting into mainstream classrooms; by the end of the year, their time in nurture groups had precipitated remarkable changes.
The resultant 90-minute film, The Nurture Room, was broadcast last week on More 4, and won the "best long documentary" award at last year's Scottish Mental Health Arts and Film Festival. It can also be seen on Channel 4's 4oD website.
The film's style is reminiscent of Etre et Avoir, the French documentary about a year in a small, rural primary. The filmmakers tried to blend into the background to ensure the children's behaviour was authentic, and there is no voiceover; the pupils' words and actions speak largely for themselves.
Two of the three main pupils - Jamie, six, and Jordyn, eight - were filmed at Royston Primary, where both worked with teacher Agnes Galbraith. We see Jordyn, who has been diagnosed with attention deficit hyperactivity disorder, spitting and muttering to a teacher to "f**k off". She is big for her age and her behaviour is unpredictable; classmates tend to keep clear of her. "If you're her age, she's quite intimidating," says Miss Galbraith.
But behind that facade is someone vulnerable: a girl hard-wired to be suspicious of others, who does not believe she is good at anything, and has no nice things to say about herself. "For some reason she doesn't like to show that side of herself," observes the teacher.
Bit by bit, the film shows Jordyn progressing in the soothing enclave of the nurture class. Squirming embarrassment cannot obscure the pride she takes when her mainstream classmates drop in to see her accept a prize. In a visit to the mainstream class, she is absorbed in times tables - earlier in the film, they had made her fidgety and crotchety.
Perhaps the most moving moment arrives when she joins a football club and plays in a match. With Miss Galbraith watching, she strides forward and scores a goal. Her reaction is bashful, as if unaccustomed to moments of jubilation.
When we last see her, Jordyn sums up the change in herself: she is good, helpful and kind, and people no longer think she is going to hit them.
At Wellshot Primary, Jason is changing, too, as he works with teacher Shirley Pearson. His initially distracted, aggressive behaviour was the tip of the iceberg; staff did not want his worst outbursts on camera. Lessons were a struggle: he pushed a piece of work away, anguished that "Nothing helps me. Nothing at all helps me."
Jason was on the waiting list for a placement in a residential school, but by the end of the film he is singing in a school show and proudly showing the film crew around the building.
At the start of filming, an interview would have been impossible, says Mr Pinder. Now, Jason waits patiently for two girls to leave the school's quiet room and strokes a teddy's fur. "I like its skin," he says. But he does not need the quiet room any more, because "I'm good now".
Mr Pinder initially visited Wellshot, Royston and St Clare's - another Glasgow primary featured in the film - for a Channel 4 Dispatches documentary, Britain's Challenging Children. His team approached thousands of schools, but only five, including the three in Glasgow, agreed to take part, which he believes testifies to their belief in their work. He soon decided the footage from the Glasgow schools was rich enough to merit another, longer film.
One of the biggest challenges was the interest a camera generates. Mr Pinder lost track of the number of great shots they had to scrap, because of "some kid pulling a face in the corner of the frame". But there was a difference in the nurture classes, where children were less self- conscious.
"They knew what to expect in the nurture room, they knew that nothing bad was going to happen in there and they felt safe," he recalls.
"We found we could get very close to the children without them really noticing or being affected. The result is the natural footage that makes up the bulk of the film."
Mr Pinder admits he was concerned when he took the finished film to show staff, knowing them to be "fiercely protective" of their pupils. "Fortunately they really love the film and what they saw that day is the film you see today," he says. "We haven't changed anything."
The Nurture Room can be bought for pound;15 from www.thenurtureroom.com
NURTURE GROUP FACTS
Nurture groups can also take place in secondary schools and young offenders' institutions. They are grounded in attachment theory, an area of psychology that focuses on the need to form secure and happy relationships in childhood.
Approaches vary, but all nurture groups have aspects in common: the whole group eats breakfast with staff, learning listening and speaking skills and seeing positive interaction between peers and adults; there are settees and soft chairs, to create a homely environment unlike a classroom; and good behaviour is rewarded, rather than relying on punitive approaches to bad behaviour.