A man is being questioned on suspicion of attempted murder after a 14-year-old girl was stabbed near the gates of her school in an attack witnessed by other pupils.
West Midlands Police said Chloe West had suffered serious wounds to her upper body and face, but was saved from even more severe injuries when bystanders confronted and detained her attacker.
An 18-year-old man, believed to be known to Chloe, was arrested outside Ridgewood High School in Stourbridge, West Midlands, at about 8.45am on Friday after initially being tackled by students, pupils' parents and teaching staff.
Superintendent Stuart Johnson praised the bravery of those who stepped in to halt the attack.
He said: "I would just like to pay tribute to the very brave individuals who, without too much thought for their own safety, intervened at the time of the incident this morning.
"They showed tremendous bravery in intervening and actually detaining the suspect and in my opinion - based on medical evidence - they clearly prevented far more serious injuries to Chloe."
Chloe is said to be in a stable and non-life-threatening condition after being airlifted to Birmingham Children's Hospital, where she is due to undergo surgery. Officers were called to reports of a girl being stabbed near the school's main gates at 8.42am and were at the scene within minutes.
Mr Johnson said: "On arrival, they saw that there was indeed a young lady, who we since know to be a pupil at the school, with serious injuries believed to be knife wounds. They also found that a young man, who we have since established does not attend the school, had been detained by members of the public here in the street."
The stabbing happened near semi-detached houses in Park Road West, a cul-de-sac which leads to the school, as Chloe walked along the pavement. Witnesses claimed the attacker arrived in Park Road West in a vehicle which had been driven to the area at high speed.
Meanwhile, a 15-year-old boy was being treated for stab wounds after he was attacked in a street in the Barkerend area of Bradford, at about 4pm on Thursday.