A 16-year-old boy has been attacked with a claw hammer in what police have described as a "horrific" assault in east London.
The victim was hit several times over the head, leaving him nearly unconscious, after being confronted at a bus stop in Poplar Park, Tower Hamlets.
He was able to escape by getting on to a bus, as passengers barred the attacker from boarding, police said. The suspect then fled the scene.
The school pupil was left needing five stitches in the back of his head and nearly lost consciousness from blood loss.
Scotland Yard called the assault a "horrific attack on a school boy" and praised the quick action of the bus driver and passengers.
CCTV footage shows the assailant approaching the victim before striking him with the hammer.
Police were called to the scene at about 4.10pm on 4 October. Officers appealed for information and released the footage on Tuesday.
The suspect is a black teenager who was wearing dark trousers and a top, police said.
Anyone with information is asked to call police on 101, or Crimestoppers anonymously on 0800 555111.