Warning: This story contains descriptions some readers may find distressing, including references to self-harm and suicide.
He was just 12, going on 13 and in Year 8, when a classmate pushed a phone into his face during breaktime.
On the screen was a recording of a live video of a man taking his own life with a gun. It happened in seconds, but the effects have lasted years.
"There are no words to express how much of an impact that video truly had on me," Frazer said, "my life would have been completely different if I hadn't seen it."
Frazer had already been struggling in the aftermath of the COVID pandemic.
But the shock of that moment, and the isolation he felt afterwards, sent him into a spiral.
"I felt lost, hopeless," he said. "I didn't want to speak up because my friends would have just been... 'man up'."
Over the last few years, his mental health deteriorated. He experienced severe depression and moments of crisis.
He even tried to take his own life.
His father, Damian, recalls one night when he had to physically intervene to stop his son harming himself.
'He wanted to hurt himself'
"He wanted to hurt himself with a knife, a big knife," he said, "I wasn't going to see my son hurt himself or worse."
He said he will be "haunted" for the rest of his life by seeing his son "break down in tears".
"He hadn't done it in a malicious, nasty way. This was pure desperation."
Frazer: 'I'd lash out'
It wasn't until last year, four years after he unwillingly saw the disturbing video, that Frazer was diagnosed with complex Post‑Traumatic Stress Disorder, directly linked to what he saw at school.
He describes "triggers" he still experiences, including the sound of a Nokia mobile phone ringtone from the video.
"It would set me off," he said. "It would make me anxious, melt down, I went into a state of uncontrollably not being able to maintain normal behaviour and I'd lash out on people because of it."
He also described being affected by "the sounds from the video of the blood running. It resonates with me a lot whenever I hear fountains, water… and those have been key points to show that this video is a big, big, big part of why I was suffering so much."
Not an isolated case
Frazer's experience is not an isolated case, according to clinicians.
Dr Emily Sehmer, a consultant child psychiatrist, said she sees similar stories far too often.
"It's very, very common, unfortunately," she said. "Frazer's case did not surprise me… there are a lot of children who have struggled in similar ways and have not come forward.
"Our services are not equipped to manage this level of mental health problems, and I don't see that number will reduce if children continue to be exposed to this kind of online content."
Last year, she notes, around 500 children a day in England were referred to mental health services for anxiety alone.
Frazer and his family are now supporting a campaign to ban smartphones in all schools - not just in classrooms, but on the journey to and from school as well.
"There's so much technology in schools today, you don't need phones in school," Frazer said. "It's unnecessary. …in the hands of people who can be naive and irresponsible."
"...a few seconds that could completely change someone's life."
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The current guidance allows headteachers to decide how smartphones are used, but campaigners argue the safest approach would be a complete ban on them in all schools.
The Department for Education said that 99.8% of primary schools and 90% of secondary schools already have mobile phone restrictions in place and said they "support headteachers to take the necessary steps to prevent disruption backed by our clear guidance".
It added: "Through the Online Safety Act, we have taken some of the boldest steps anywhere in the world to ensure children have age-appropriate experiences online, protecting them from harmful content.
"We are striking the right balance: protecting children while ensuring they can safely benefit from the digital world, without risking isolation or cutting off access to vital services, especially to the most vulnerable."
Officials point to new legal duties requiring social media companies to protect under‑18s from harmful material, including content linked to self‑harm and suicide, with Ofcom able to issue significant penalties for breaches.
:: Anyone feeling emotionally distressed or suicidal can call Samaritans for help on 116 123 or email jo@samaritans.org in the UK. In the US, call the Samaritans branch in your area or 1 (800) 273-TALK
