A teenager who stabbed a student to death in a row over conkers has had his sentence increased by the Court of Appeal.
Sixteen-year-old Ochaine Williams - who can be named for the first time today - was in the dock at the London courtroom to hear three judges increase his minimum term from 10 and a half years to 12 years.
Williams, of Victoria Road, Edmonton, north London, was 15 when he killed architecture student Steven Grisales after he challenged youths who were throwing conkers in their spiky husks at him.
Mr Grisales, 21, had been shopping for his grandmother and was on his way to Silver Street station in Edmonton when he was attacked in College Close in August 2011.
Williams denied being the killer, but was found guilty of murder at the Old Bailey earlier this year.
Judge Richard Marks ordered him to be detained at Her Majesty's Pleasure, with the minimum term of 10 and a half years.
But at the Court of Appeal, Lady Justice Hallett and two other judges agreed with submissions made on behalf of Attorney General Dominic Grieve that the original minimum term was "unduly lenient".
Lady Justice Hallett, when increasing the sentence, said: "This was yet another example of mindless violence on the streets of London.
"Mr Grisales, an innocent young man, has died simply because he dared to stand up to bullies."
The court heard that Williams has made an application for leave to appeal against his conviction.
An order suspending publication of his name pending an appeal was lifted by the three judges following a media application today.
Lady Justice Hallett said it was a "tragic case".
Mr Grisales had "made the fatal mistake of daring to remonstrate" with the group of youths throwing conkers.
The student's mother, Jasmid, of Enfield, north London, "spoke movingly" in a victim impact statement of the family's "devastation and profound distress at the needless loss of her son".
Mr Grisales, a man of "impeccable character and great promise" was clearly dearly loved, said the judge, and "the lives of his family will never be the same".
It was argued on behalf of the Attorney General that the original minimum term failed adequately to reflect the gravity of the offence and "public concern over offences of this nature".
Imposing the new minimum - the least an offender must serve before becoming eligible to apply for parole - the judge said that if Williams was deemed safe to be released after that term he would still be in his 20s with his whole life ahead of him.
She added: "In a split second of anger he denied Mr Grisales that life.
"We understand that it may seem to his family that the result is unfair. However, we hope that they understand we are bound by a sentencing regime laid down by the law."
Mr Grisales had returned to Britain from Argentina to take up a scholarship to study architecture at Westminster University.
His organ donations following his death helped to save the lives of three women.