London police said they had arrested a teenager after a 15-year-old girl was stabbed to death on her way to school on Wednesday, stoking fresh concern about the scale of knife crime in the UK.
Emergency services including an air ambulance were called to the scene in Croydon, south London, at around 8.30 am (0730 GMT) following reports of a stabbing.
Paramedics battled to save the girl but she was pronounced dead at the scene 50 minutes later, police said, adding that a 17-year-old boy was later arrested.
London mayor Sadiq Khan said he was "heartbroken" by the fatal incident and pledged to "continue working day and night to end the scourge of knife crime in our city".
According to official figures, 99 people under the age of 25 were killed in England and Wales with a knife or sharp object in the year to March 2023. Of those 13 were under the age of 16.
The deaths were among 50,000 stabbing incidents in the year to March 2023, a five percent increase on the previous year and a 75 percent increase on a decade ago, the figures from the Office for National Statistics showed.
Police said the suspect in custody was being questioned by detectives.
"Our immediate thoughts are with this young girl’s family who are facing the most tragic of news. Our officers are with the girl's family to support them," said Chief Superintendent Andy Brittain of the Metropolitan Police.
Victor Azare, a 50-year-old security guard on his way home after a night shift, said he and others chased a boy in a school blazer after seeing him stab the girl in the neck with a knife that was "black, thin and about a foot (30 centimetres) long".
"We tried to catch him and a lot of people tried to save the girl. I was so shocked, I was shaken. It's somebody’s daughter," he told British media.
Media reports said the girl had just got off a bus at the time and appeared to have been having an argument with a boy who then attacked her.
The girl, whose identity has not yet been released, was a pupil at Old Palace of John Whitgift School, a private girls' school in Croydon.
"We are deeply shocked by the senseless and tragic death of our much-loved and valued friend and pupil," the school said in a statement.
"It will take some time for the Old Palace community to come to terms with this terrible news.
"Above all, we send our love and deepest sympathies to the girl's family at this unimaginably distressing time," it added.