A man has been detained for stabbing a 17-year-old boy to death outside a south London Tube station.
Tammuz Brown, 18, attacked Malcolm Mide-Madariola with a hunting knife near Clapham South station last year.
The Old Bailey heard the victim was killed after he stood up for a friend who the defendant had a “trivial” grudge against.
Brown, of south-east London, was found guilty of murder and possessing a knife and will serve at least 16 years.
The jury was told Brown thought Malcolm’s friend had stared at him as they passed in the corridor of a sixth form college, days before the killing.
He then asked his friend Treynae Campbell to bring a 12-inch (30cm) knife and on 2 November lay in wait for the boy after college.
Prosecutors said Malcolm was an innocent victim who “bravely sought to stand up to Brown, for which he paid with his life”.
Judge Wendy Joseph QC said the killing was over a dispute which “could hardly have been more trivial”.
In a statement, the victim’s father Olumide Wole-Madariola told the court his son was “a young man driven by compassion, by faith, by a fierce sense of justice and a heart full of love”.
“What he was known for as a child was what eventually took his life – peacemaking and standing up for others in need,” he said.
Campbell, 19, from Sydenham, previously admitted having a blade and was handed 28 months at a Youth Offenders Institution at an earlier hearing.