Victim Steven Grisales

A 15-year-old boy who stabbed a promising architecture student to death for complaining about having conkers thrown at him has been jailed for a minimum 10-and-a-half years.

The youth, who cannot be named for legal reasons, later boasted of being a member of the Tottenham-based Northumberland Park Killers gang, or NPK, while on remand in prison.

The Enfield youth was jailed last Wednesday at the Old Bailey but is expected to appeal his conviction, having denied murder throughout, blaming a friend.

He was found guilty of murdering 21-year-old Steven Grisales as he made his way to Silver Street station in Edmonton on August 31 last year.

He was pelted with conkers, still in their spiky shells, along with other pedestrians, thrown by a group of teenagers who he got into a row with.

As the argument continued the teenager pulled out a knife and stabbed Steven in the heart. He died in hospital a day later.

Steven’s mother, Jasmid Grisales, said the verdict “does not change our lives in any way because we lost Steven forever and he is not coming back to us”.

She added: “We have to carry this cross for the rest of our lives.

“Steven was always loved by absolutely every person who had the privilege of knowing him and calling him a friend, cousin, nephew, grandson, son or brother. He always gave without expecting anything in return and he always tried for everyone around him to be happy.

“This result can show that in a way it is justice and people should start learning that for every wrong you do, sooner or later you have to pay the price.”

Detective Inspector Richard Beadle, senior investigating officer at the Homicide and Serious Crime Command, said: “Steven did no more than stand up to an unruly youth and for that he has lost his life.

“But for the courageous intervention of a local resident I am convinced the knife attack would have continued.

“The man placed himself in front of Steven while the youth was repeatedly attempting to stab him again.

“The defendant has shown no remorse and has continually lied about his involvement. He was even prepared to blame the stabbing on his friend if it meant he could escape conviction. His arrogance and contempt for others belies his age.

“I am extremely grateful to those witnesses who came forward - without them we would not have achieved a successful prosecution.

“Sadly there were others, known to the defendant, who held vital information and refused to help the inquiry. In fact they did all they could to deter the investigation and, ultimately, justice.”