John Bevan, for the prosecution, described how Mr Lawrence, a father of four, staggered through a crowd of pupils back towards the school where he collapsed after being knifed in the chest.
"It was decided to open his chest then and there in an attempt to save his life," said Mr Bevan. "An emergency left thoracotomy was performed to allow internal cardiac massage.
"He was operated on at the hospital from 4.30pm to about midnight when it became obvious that there was no chance of survival and he was declared dead."
Earlier, Mr Bevan described how Mr Lawrence had been at the main gate of St George's Roman Catholic School in Maida Vale, north-west London, seeing pupils off the premises for the weekend. When he noticed one of his pupils being attacked, he ran towards the fracas. "Inevitably, his reasons must have been to try and find out what was going on and to prevent injury to one of his charges," said Mr Bevan.
It was then that he came face to face with the defendant - a 16-year- old boy who cannot be named for legal reasons - who had become separated from the rest of the self-styled Triad-type gang.
Mr Bevan said the headmaster "adopted a non-threatening and conciliatory stance ... Even if he had made a grab for the defendant's shoulder, which is the most anyone described him doing, it was no more than merited the circumstances".
The defendant then allegedly "slapped or punched" Mr Lawrence and kicked him on the leg. Producing a knife, which was hidden in his waistband, he stabbed him once on the left side of the chest just under the the left armpit. Mr Bevan added: "It was wholly unnecessary, wholly unprovoked, gratuitous violence for its own sake."
The boy returned to the gang "looking worried", Mr Bevan alleged, and "told the others `I've made a mistake, I've stabbed a teacher'. When someone asked why, he said `shut up, it wasn't my fault, we better split up' ". The defendant then went to an amusement arcade where he confided to a former gang member that he had stabbed a teacher. Later that night, a knife was found discarded nearby.
Mr Bevan showed the court a 10-inch single-edged knife with a blade about six-and-a- half inches wide, the top of it double-edged. "Most of the cuts on Philip Lawrence's clothing had the appearance of being made by a double-edged weapon and test cuts in the laboratory using the knife produced similar cuts," he said.
The 16-year-old boy denies murder and two further charges of conspiracy to cause grievous bodily harm and wounding with intent. A 15-year-old denies the latter two charges.
The trial continues today.Reuse content