Nine-year-old Lennox poured a large blob of red paint on to his palette. Reaching over for the glitter paints, he matched it with a dollop of sparkly red. “This is blood,” he announced, mingling the two together to form a glutinous liquid.

Then he dipped his finger in the mixture and slowly, carefully, wrote two words in large letters: HELP ME. Finally, he smeared paint over both hands and slapped them down on to the middle of the page.

“He wanted the image to look like someone who was severely injured, who needed help,” says Stephen Adams-Langley of school-based counselling charity The Place2Be. “But the powerless and injured victim was him.”

Schools are filled with pupils like Lennox: children who quietly juggle extraordinarily difficult home lives with the casual mundanities of school. One in 10 children between the ages of five and 16 suffers from a diagnosable mental-health disorder - equivalent to three pupils in every classroom. Of these, nearly 80,000 experience severe depression, including 8,700 children under the age of 10.

Indeed, the majority of adults with mental-health problems first experienced them in childhood, according to the mental-health charity YoungMinds.

Lennox may be unusual, therefore, but he is not unique. A number of teachers have been surprised, and then perturbed, to discover that disturbing images in artwork or essays are not the product of fevered schoolchild imaginations, but the outward expression of a complex, internal balancing act. Or, in some cases, an all-too-literal account of their lives.

“If a child is asked to write about something scary or something that’s made a big impression, they will take that literally,” says Phillip Hodson, fellow of the British Association for Counselling and Psychotherapy. “And some have troubled lives.”

Bryony’s creative-writing exercise began with an argument: unlike the rest of her GCSE English class, the South Wales schoolgirl did not want to write a short story. “She’s a salt-of-the-earth kind of girl, Bryony,” says Lois Banks, her English teacher at Bryn Hafren Comprehensive in Barry. “She isn’t into English at all - it’s too flowery for her. She said, `I can’t do that - I don’t have any imagination’.”

And so Ms Banks looked through the coursework requirements and found Bryony an alternative exercise: she could produce a piece of autobiographical writing instead. “My guidelines were: write about a holiday, or about the best day of your life,” she says. Bryony nodded: this required limited imagination.

Several days later, she handed her completed essay in. “I can picture the day in my mind like it was yesterday,” it began. “My brother Ryan was only 15, making me 13. It was a Tuesday.

“Ryan had been involved in a gang fight. He and his five boys had beaten up two men so badly that they had to be hospitalised. When mum went to the police station, she had seen the CCTV footage. She said it looked as though the boys were trying to kill their victim. Their actions seemed deliberate.”

During lesson time, Bryony had merely discussed ideas about her holidays, toying with Ms Banks’ suggestions. “I wasn’t expecting anything particularly interesting or original or impressive,” her teacher says now. “She was so negative about short-story writing, I thought she’d do the bare minimum. This was not what I was expecting.”

But, says Phillip Hodson, this is the crucial point: children’s understanding of what is expected of them is inevitably coloured by their own experience. “There’s no universal script wired into children,” he says. “The only universal script is how to survive in your environment. If your parents are completely bonkers and cruel, you adapt. Then, when you come out into the world, you might not fit completely, might not react to cues in the same way as everyone else.

“When they’re asked to write something, they will write from the perspective that they’ve found to be normal. They’re not necessarily going to have the kind of deceptive ability that a mature adult would display. So if a teacher says, `describe what you did over the summer’, you might find them describing horrendous or horrible stuff. The child is sort of leaking, but isn’t really aware of it.”

Malachi was a Year 2 pupil at a south London primary. His class was regularly asked to produce pieces of creative writing: the latest task, to write a story with a clear main character, was no different from those that had come before.

This time, however, Malachi wrote about a boy whose angry father regularly beat his mother. The boy was very unhappy: his mother had said that his father had to leave home, but the boy did not want his father to go. So he found a magic wand and used it to paint colours on his bedroom ceiling, cheering himself up again. “The boy was obviously telling a story about a real situation, and his wish that it would all be all right,” says Mr Adams-Langley.

Lennox, too, used school-based exercises in creativity to express his desire to control his own reality. Before his finger-painted cry for help, he had produced a series of pictures in which a small boy was being squeezed into irrelevance by groups of other children. In one, children crowded in on each other in the centre of the page while a tiny Lennox figure was squeezed into the bottom corner.

It transpired that his mother was a serious alcohol and drug addict. The oldest of five siblings, Lennox was left to look after the others: it was he who changed nappies, who went grocery shopping, who prepared the family’s meals.

“Lennox was just washed out,” says Mr Adams-Langley. “He found other children frustrating and exhausting and difficult. He felt overcrowded, squashed, oppressed by them. When we eventually understood that the family was living in three rooms and he was the carer, it all made sense.

“He couldn’t say, `I’m only nine years old - I don’t want to be changing nappies and putting my brothers and sisters to bed.’ The images allowed him to draw out his desperation, convey his frustration. Even making something up, there’s a kind of truth. Children play out the drama of their lives through metaphor.”

At Bryn Hafren, Bryony had missed Ms Banks’ initial deadline, and it was only after days of nagging that she finally handed in her essay. They were at a school parents’ evening; Ms Banks was speaking to her parents. “By the way,” Bryony said, with cultivated off-handedness, “I’ve done that story.” And she practically hurled it across the desk.

Ms Banks did not begin to read the essay until she was at home. Bryony’s words were simple, literal and matter-of-fact. “That night, I lay awake in my bed, thinking, `He couldn’t really, could he?’” she wrote of her brother’s attack on the two men. “Ryan? No, I didn’t believe it. Why would he? I didn’t believe anyone. Anything they said, I blocked it out.”

Ms Banks stopped and put down the essay. “Oh, God,” she thought. “Oh, God.” She had known that Bryony had an older brother. And the girl would talk about her own past naughtiness, making it clear that she had become better-behaved after something had happened to her brother. But the exact details had never been clear.

“Because Bryony didn’t particularly like writing anything, I’d almost forced her into it,” Ms Banks says. “There was a safety net there for her: I’d forced her to write something autobiographical. So she could shift the blame on to me, if she needed to.

“English teachers everywhere have this, I think. We’re more open to revelations. You often discuss quite controversial things in class, so you’re always prepared for some kind of fall-out. It’s almost as though children don’t understand that their writing is real and will have implications.”

At eight-year-old Malachi’s south London school, his class teacher had no idea that the boy had problems at home. Neither did Malachi: this was why he had thought nothing of writing these problems into his story. “For many children in this situation, it’s their version of normal,” says Mr Adams- Langley. “So adults have to do the thinking on behalf of the children.”

Malachi’s school employs a counsellor from The Place2Be, so his teacher referred the case directly to him. The counsellor then invited Malachi and his mother to come to his office for a chat. “This sort of situation is not unusual,” Mr Adams-Langley says. “Domestic violence and abuse are quite common. Usually the woman will be very intimidated, very ashamed. We have to move very sensitively, very slowly.”

In fact, teachers should not only be aware of the need to react slowly and sensitively, but they should also question carefully whether there is any need to react at all. “There’s a delicate balance here,” says Trish O’Donnell of the children’s charity NSPCC. “Stories, any kind of creative expression or play - that’s how children communicate. It helps them learn to understand the world. It’s important to realise the dangers of taking that at face value.”

For example, she says, a nightmare scenario described in a story might prove to be nothing more than a literal nightmare: the child using a creative-writing exercise to process the emotions generated by a dream. Writing, therefore, must be placed in context. “Does the child have any other behavioural problems?” Ms O’Donnell says. “Are they missing school? Are they frightened when someone raises their voice? You need to ask open questions, have an open mind.”

Ms Banks knows this from personal experience. During her first year of teaching, she set a mock GCSE exam for her Year 11 pupils. The creative- writing exercise was fairly straightforward: write a story entitled “A Night To Remember”.

Marking the essays afterwards, she discovered that one girl had written graphically - too graphically - about a sexual assault. Of course, Ms O’Donnell says, teachers cannot ignore something like this. But, she adds, neither should they leap to any unwarranted conclusions. “We all have our own ideas of what children should and shouldn’t know,” she says. “You’d be better probing around specific words: `That’s quite a grown-up word - I wonder where you learnt that.’ Again, it’s about asking open questions.

“It’s the same as if a pupil produced something academic and you thought it was a bit advanced for their age. Teachers have the skills to ask the right questions. But because this is outside their comfort zone or professional expertise, they might feel de-skilled.”

Young, inexperienced and new to teaching, Ms Banks simply took the girl aside and asked her whether her story was true or invented. The girl shifted uncomfortably in her seat, looking over the teacher’s shoulder. “Erm . erm,” she said. “Made up.”

“I shouldn’t have put her in that position,” Ms Banks says now. “It made me feel very, very naive; I found it very hard to handle. It’s difficult - kids do seem to pick somebody they want to talk to. They want to get their story across.” Out of her depth, she passed the girl’s details on to a child-protection officer.

“Working in a comprehensive, you see a lot of hard-faced, streetwise girls,” she says. “But things like this remind you that, for all their 21st-century bravado, they’re just children. Underneath it all, they’re very scared and inexperienced little girls.”

Hannah was one such child. While still a toddler, the Nottingham schoolgirl had been severely physically abused by her parents: her hands bore scars where her father had poured boiling water over them. He was now in prison, serving a life sentence for murdering Hannah’s brother. Unable to concentrate in lessons, unwilling to sit down when told, by the age of 11 Hannah was loud, volatile and uncontained.

Referred to a counsellor, she began to write stories. The father in her stories had been the victim of a miscarriage of justice: unfairly imprisoned, his thoughts were only for his surviving child, a little girl.

Hannah would write letter after letter to this imagined father and then instruct her counsellor to shred them immediately. Writing allowed her to express her frustrated longing for a lost father, but she was too emotionally immature to cope with these feelings: once expressed, they needed to be destroyed.

“For an outsider, of course the child needs to be taken away from parents like that,” says Mr Adams-Langley. “But it’s very difficult for an outsider to appreciate how conflicted a child can be. They can still have love for an abusive parent. Writing it out can be a way of helping a child acknowledge and process those feelings. They need to be listened to, without someone saying, `You’re better off without him’.”

With almost painful honesty, Bryony used her creative writing to outline her love for her violent brother. “Mum said three words: `I’m sorry, love’,” she wrote. “I never knew that three simple words could make someone feel like their whole world had been tipped upside-down. I sat with the phone to my ear, sobbing.

“It was as if someone had ripped me apart. I felt like a part of me was missing. Later, I sat in his room, looking at his things. Crying. A little girl who’d lost someone who meant the world to her. Ryan had been sentenced to 12 months in prison.”

The rawness of the emotion made it difficult for Ms Banks to know how to respond. “It could almost have been a bit embarrassing for her if I’d made a big deal about it,” she says. “But I did have a quiet word with her, told her how impressed I was. She was all, `Yeah, OK, whatever. Oh, shut up.’ She didn’t like to show that she was pleased about having this praise.”

Heartbreakingly personal though it was, Bryony’s essay was also a piece of GCSE coursework: Ms Banks would need to give it a grade. She read through the final paragraphs again: “Ryan’s experience taught me that nothing is worth losing your family. If I’m honest, my behaviour wasn’t good in school or at home before Ryan was arrested. I could have gotten into trouble just like him, but I changed my ways. He couldn’t change what had happened to him, but he changed what could have happened to me, and for that I am thankful.”

“Because it’s so personal, it makes you think, `That’s brilliant’,” Ms Banks says. “You have to distance yourself and think more mechanically. You want to reward her for her honesty, but that’s not quite how marking works.”

In the end, she awarded Bryony 15 out of 20: a high B grade. Parts of the essay, she said, were excessively conversational; other sections were longwinded or irrelevant. The mark, however, was Bryony’s highest that year.

The key, says Trish O’Donnell, is not to overreact to creative writing or artwork, no matter how shocking. “Don’t forget that you’re marking it for language, content, structure,” she says. “But don’t forget the emotional content, either. Check and see if the child needs help and support.

“And communicate with the parents, too. Be prepared if they say, `Yes, there’s a problem, and we want to talk about it’. And have a strategy in case they shut down as well. Have lifeboats ready.”

And so, rather than confronting nine-year-old Lennox with the horrifying melodrama of his own self-expression, his school took a more considered, long-term approach. The boy’s father, it transpired, was estranged from his mother. A learning support assistant, he seemed a potentially stable, responsible figure in the boy’s life.

The school therefore contacted the father, explained Lennox’s situation, and asked whether he would be willing to take custody of the boy. After lengthy discussion, he agreed. “There are very rarely happy endings in our work,” says Mr Adams-Langley. “This is as close to it as you get.”

Children’s names have been changed.

www.theplace2be.org.uk.