A 16-year-old boy killed himself after asking ChatGPT for the “most successful” way to take your own life, an inquest has been told.

Luca Cella Walker, a private school pupil from Yateley, Hampshire, died on 4 May last year.

An inquest at Winchester coroner’s court heard on Tuesday that, hours before his death, Walker had asked the generative AI chatbot for the “most successful” way for someone to kill themself on a railway line.

At the time of his death, he was studying at Sixth Form College Farnborough. He had recently graduated from Lord Wandsworth College near Hook, Hampshire. The court heard that the school had a “bully or be bullied” culture, which had been a “formative” factor in his mental health struggles.

Walker, described by his family as “kind, sensitive and calm”, had told his parents he was going to his job as a lifeguard but instead travelled to a train station, where he took his own life.

His parents, Scott Walker and Claire Cella, told the inquest they had had no idea about their son’s mental health struggles and described it as an “invisible battle”.

DS Garry Knight from the British Transport Police, who investigated Walker’s death, told the inquest: “They found he had been on ChatGPT the night before, at about 12.30am, asking for advice on the most successful ways to commit suicide on the railway. It makes quite chilling and upsetting reading.”

Knight added: “It is built in to say you can contact organisations for help such as Samaritans, but Luca had sidestepped that, which ChatGPT accepted and gave the most effective ways people can [kill themselves] on the railway.”

Coroner Christopher Wilkinson told the inquest of his concerns about the impact of AI software but added he felt unable to act due to its growing scope.

Wilkinson said: “It’s clear from what I’ve read that he was asking for specifics. Thankfully, perhaps the only good thing is that ChatGPT does seem to be applying an element of worry about why these questions are being asked, but it certainly doesn’t stop the conversation.

“It’s sidestepped by the individual saying he’s not looking for himself but he’s looking for research purposes.”

Wilkinson confirmed the cause of death was multiple traumatic injuries and said Luca had died by suicide.

A spokesperson for Lord Wandsworth College said Walker was a “very well-liked and valued member of our community” remembered for “the friendships he built and the positive impact he had on those around him”.

They added: “While the school was not called to give evidence in the inquest proceedings, we take any concerns about student wellbeing extremely seriously.

“Our school community is built on a strong culture of respect and support, reflected consistently in student feedback and independent inspection. We remain fully committed to ensuring every pupil feels safe, supported and valued.”

A spokesperson for OpenAI, which developed ChatGPT, said: “We have continued to improve ChatGPT’s training to recognise and respond to signs of mental or emotional distress, de-escalate conversations and guide people toward real-world support.

“We have also continued to strengthen ChatGPT’s responses in sensitive moments, working closely with mental health clinicians.”