The family of a teenager who was stabbed to death during a knife awareness session are demanding answers from the local council, saying it was “incredible” that protections weren’t in place to prevent his death.

Hakim Sillah, 18, was killed on Thursday evening following an attack at Hillingdon Civic Centre in High Street, Uxbridge, while attending the event at the council-run youth offending service. A 17-year-old boy has been charged with the murder and is due to appear in court on Monday.

Mr Sillah’s mother had dropped him off shortly before, after picking him up from their home where he had spent the day caring for his six-year-old asthmatic brother, according to his aunt, Nyamakoro Silla.

Ms Silla, 54, told The Independent the family felt that Hillingdon Council had “failed to protect” her nephew and the other young people in the session, despite the risks being obvious.

“This was a session on violent crime and weapons, so you would expect that some protection would be given to those who attend the course – anyone would expect that. To just allow people to come into the building and not have any sort of protection… It’s incredible,” she said.

Flowers laid out for Hakim Sillah (Nyamakoro Silla)

“It’s council premises. People should have been searched before they went in and checked for if they were in an angry state of mind. It was on their premises, on their invitation, and he wasn’t protected.”

She said Mr Sillah, who had turned 18 two weeks before his death and was in his last year of college, had been attending the session to help him navigate the challenges of living in a city with high levels of knife violence, but that he was a “polite, kind boy” who had “never been any trouble to anybody”.

Ms Silla added that her nephew had been asked by the youth offending service if he could be a spokesperson to help other young people, and that he had been “pleased to do that”.

“He was a good boy who always wanted to do the right thing. He was very caring. He loved his younger siblings. He loved his mum. He always had a smile on his face. He liked his music, a bit of rapping. He wanted to go travelling. All of those things that young people dream about,” she said.

“There were no issues whatsoever, and then somebody just goes and murders him right there on a Hillingdon Council premises, just like that.”

Describing the impact his sudden death had had on his mother – her sister – and two younger siblings, she said: “They’re devastated. His mother is beside herself. She had big hopes and dreams for him. She dropped her son off that day at council premises. If anybody had said to her this would happen, she would never have dropped him off there.”

Ms Silla added: “We want Hillingdon Council to come up with the answers. We want to know what went wrong. They are going to have to accept responsibility for his death.”

Hillingdon Council said: “This matter is being investigated by the police and we are unable to comment further at this time. Our thoughts are with the victim’s family.”

Police said the fight broke out between males at the civic centre, and that a second young man “bravely” tried to intervene to break up the fight and as a result was also stabbed, but that his injuries weren’t life-threatening.

Detective Chief Inspector Noel McHugh, who is leading the investigation, said: “This is an absolute tragedy. A young man with his whole life ahead of him has been fatally attacked and his family are absolutely devastated.

“We are doing everything we can to find those involved. We want to hear from anyone who was there so we can understand what happened prior to the stabbing taking place and events immediately afterwards.

“Whilst we have made an arrest, and we are not seeking any other suspects, we urge anyone who has information on what took place to come forward.”