A father whose teenage son was stabbed to death at a house party is calling for new legislation to protect bereaved children and introduce knife crime education in schools.

Martin Cosser’s 17-year-old son, Charlie, was killed in July 2023 at a party in Warnham, West Sussex. Two days later, Martin stood by his hospital bed and made him a promise: that he would never be forgotten.

That vow became Charlie’s Promise — a charity now campaigning for Cosser’s Law, which would make knife crime education compulsory from Key Stage 2 and give anonymity to under-18 relatives of victims.

Martin said his daughter Eloise, who was just 15 when her brother was killed, was thrust into the media spotlight in the days after his death, while the identity of her brother’s alleged killer – also 17 – was legally protected.

“Everything favours the defendant,” said Martin. “We were treated like second-class citizens. This country failed us and continues to fail families like ours. Where was our protection? Where was Eloise’s? She was a child too.”

The Cosser family’s grief has translated into tireless activism. Martin has already joined Prime Minister Keir Starmer’s national knife crime task force and has met twice with the policing minister, Dame Diana Johnson, who has written to the Department for Education in support of introducing mandatory knife crime awareness at primary school level.

“We talk about road safety and fire safety at that age – why not knife safety?” he said.

At a recent event at Charterhouse School, where Charlie worked as an apprentice groundsman, Martin said: “My talks give people a window into our world, how one decision, one moment in time, has ruined so many lives. ”

Local MP Jeremy Hunt called him “the most determined and formidable campaigner I’ve ever met,” adding: “He’s banging down doors in Whitehall — and I think he’ll get results.”