A 16-year-old boy has been detained for killing a former friend after the pair traded insults on Facebook.
Salum Kombo, 18, was stabbed in the chest in Bromley-by-Bow, east London, in December after calling his killer, then 15, names including “pussy”.
The trial heard the boy, who was found guilty of murder at the Old Bailey in May, could not take the “loss of face”.
The teenager, who cannot be named, has been ordered to serve a minimum of 14 years.
Sentencing the boy at Southwark Crown Court, Judge Nicholas Loraine-Smith said: “There was nothing brave about what you did.
“This was quite simply an act of cowardice, as so many stabbings are.”
David Jeremy QC, prosecuting, said: “A young man has lost his life following a petty dispute and a perceived loss of face by the perpetrator.”
Mr Jeremy said a previous friendship between Mr Kombo and the defendant had turned to “hostility” and they had a fight last summer after a football match.
The court heard that on the night of the murder, the killer had been with friends outside a fish bar.
The trial heard how they tried to calm him down when he became angry and started talking about stabbing the older youth.