A woman was jailed for 12 years today for killing a 15-year-old boy, who was stabbed at Victoria underground station.
Victoria Osoteku, 20, was said to have played a pivotal role in the attack in central London, in which Sofyen Belamouadden was knifed in front of horrified commuters.
She was seen on CCTV kicking him in the head as he lay dying on the ground after the 12-second attack by rival school pupils.
Sofyen was stabbed nine times to the body and suffered wounds to his heart, a lung and major blood vessels.
Osoteku was found guilty of manslaughter at the Old Bailey in the latest of a series of trials of 20 defendants from south London.
Osoteku, of Deptford, south London, was the only female charged in connection with the incident in March 2010, and spent 19 days in the witness box.
Judge Christopher Moss ordered that Osoteku, who was 18 at the time of the incident, be detained for 12 years.
He also sentenced her to eight years concurrently for conspiracy to cause grievous bodily harm.
The judge said Osoteku must share part of the responsibility for the death because she assisted in buying a set of knives during her lunch hour.
A witness said she had been "gloating" about what happened the following day at her sixth form college.
Judge Moss added: "You were seen to deliver the final kick to Sofyen as you were the last of the group to run away."
Osoteku nodded to the judge in acknowledgement before she was led to the cells.
Last week, three youths were given life terms for murder and three others were ordered to be detained for 12 years for manslaughter.
Sofyen had dreamt of playing football for England and his death has left his family devastated, the court heard.
The "ferocious and merciless" attack was the horrific end of a minor confrontation the day before in the fast food area of Victoria mainline station between pupils from two west London schools.
Osoteku was one of the teenagers responsible for setting up the fatal showdown.
The A-level student sent messages by phone and on Facebook arranging the clash between pupils from the rival schools.
Sofyen died after being chased by about 20 pupils across the Terminus Way concourse and into the Underground station.
Osoteku was behind a youth who led the charge with a Samurai sword. Other youths were armed with a flick knife and a Swiss army knife, machetes and screwdrivers.
Sofyen fell down the stairs into the ticket hall and was attacked on the ground by a smaller group.
She denied the charges during a five-month trial. She said she did not kick the victim and sobbed: "I nudged him with my foot to see if he was OK."