A 19-year-old has been sentenced for life with a minimum term of 26 years for the murder of Jodie Chesney.
Drug dealer Svenson Ong-a-Kwie and his runner, a 17-year-old boy, were found guilty of murder during a trial at the Old Bailey earlier this month.
Judge Wendy Joseph sentenced the 17-year-old to life with a minimum sentence of at least 18 years. The judge lifted reporting restrictions on his name, which can now be revealed as Arron Isaacs.
She said that Jodie's death led to a "world of anguish" for her family and that Jodie was the victim of "callous, casual and irresponsible violence" which had shocked the community "to the core".
Schoolgirl Jodie, 17, was stabbed while talking and listening to music with a group of friends in Amy's Park in Harold Hill, Romford, on 1 March.
Co-defendants, Manual Petrovic, 20, and a 16-year-old boy, who also cannot be named, were cleared of murder after the jury deliberated for less than six hours.
Ahead of the sentencing today, Jodie's family members spoke about the impact of her death.
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Eddie Coyle, the boyfriend of Jodie, has paid tribute to his girlfriend in a statement read out on his behalf.
Coyle, who suffers from post-traumatic stress disorder after Jodie collapsed in his arms, said: "Jodie was funny, silly, she always made fun of me and she had a bright future ahead of her.
"She was full of energy and was always out doing something. We had been going out for three months.
"I've never lost anyone before and for the first funeral I've gone to, to be my own girlfriend's is incredibly hard. I loved her."
Jodie's father Peter Chesney told how his life has been "destroyed".
Mr Chesney said: "I have lost the most precious human being I will ever know. I have no idea how I'm going to continue my life or come to terms with the loss.
"I have a fantastic daughter Lucy and we are leaning on each other throughout this tragedy."
The trial heard Jodie was unlikely to have been the intended target of what is thought to have been a drug dispute.