Police said they did not believe the incident was terrorism-related and there was no ongoing threat to the wider community.
Police tasered and arrested the man after the incident near Hainault in east London. Video footage showed a man wielding what appeared to be a sword.
“It is with great sadness that I confirm one of those injured, a 14-year-old boy, has died. He was taken to hospital after being stabbed and sadly died shortly afterwards,” London’s Metropolitan Police Chief Superintendent Stuart Bell said.
He said it was not believed to be a targeted attack.
London’s Metropolitan Police Assistant Commissioner Louisa Rolfe told reporters a 36-year-old man had been arrested on suspicion of murder and was currently in hospital, having suffered injuries when his van collided with a building.
Two members of the public and two police officers were in hospital with non-life threatening injuries. The two police officers had stab wounds requiring surgery.
