Key Facts

• The attack happened at Milford Haven Comprehensive School in Pembrokeshire on 5 February.
• The boy followed the teacher into an empty classroom and suddenly stabbed her in the head.
• The teacher feared she might die and suffered injuries to her head, back, and hands.
• The boy was found guilty of wounding with intent but not guilty of attempted murder.
• The boy said he brought the knife as part of a "game" with friends and claimed the stabbing was an accident.
• He admitted to having a knife on school grounds, which is illegal.
• The teacher will start therapy for post-traumatic stress disorder (PTSD).
• The judge sentenced the boy to four-and-a-half years in youth detention, noting the attack showed planning.
• The boy is expected to be released after serving half the sentence, depending on certain rules.