Learco Chindamo, 16, bent his head but showed no emotion as the jury of six men and six women unanimously found him guilty after three-and- a-half hours of deliberation.
Sentencing the youth to be detained during Her Majesty's pleasure, the Common Ser-geant of London, Judge Neil Denison said: "Philip Lawrence was a good man and an inspirational teacher.
"He dedicated and directed his life to providing a future for young people in his care. You took that life and diminished that future."
Along with his co-defendant, a 15-year-old youth who cannot be named for legal reasons, Chindamo was also found guilty of conspiring to cause grievous bodily harm and wounding the 13-year-old boy whom Mr Lawrence was trying to protect when he was killed. The judge passed four-year concurrent sentences on Chindamo for the offence, while the 15-year-old youth was remanded for pre-sentence reports.
Shortly after the verdicts were announced, the police officer who has maintained close contact with the Lawrence family, Detective Constable Robin Lane, read out a short statement on behalf of Mr Lawrence's widow who had attended the trial throughout.
"Mrs Lawrence described her husband's murder as an earthquake which has destabilised the very foundations of their lives," he said.
During the four-week trial, the court heard how Chindamo had led a Triad- style gang to St George's Roman catholic School in Maida Vale, north-west London on 8 December last year to "sort out" a 13-year-old pupil who had fought with one of their friends.
The 12-strong gang arrived at the school, dressed in baseball caps and hoods, and set upon the pupil, who fled with head wounds to a nearby house.
Mr Lawrence intervened to stop the fight and came face to face with Chindamo, who punched and kicked the headmaster and then stabbed him in the chest. The teenager then ran off to join the rest of the gang in a neighbouring street where he admitted he'd "made a mistake" and had stabbed the headmaster.
Within hours of the attack, Chindamo was back at one of his regular haunts, an amusement arcade in London's West End, bragging to another friend of what he had done.
Immediately after the foreman of the jury delivered the verdict, the judge lifted a court order which had prevented the press from publishing Chindamo's name during the trial. His 15-year-old co-defendant will remain anonymous.Reuse content