LONDON, United Kingdom -- A judge in western England on Thursday sentenced a teenager who stabbed a teacher in a school corridor to 14 months in youth detention, amid concern about rising knife crime in the UK.

The 15-year-old boy, who cannot be identified because he is aged under 18, had previously admitted attempting to unlawfully and maliciously wound the maths teacher at Tewkesbury Academy in Gloucestershire.

He had also earlier pleaded guilty to a charge of possessing a bladed article.

His sentence follows a fatal knife attack on a 15-year-old girl in south London on Wednesday.

Bristol Magistrates' Court heard how the boy in Tewkesbury covered his face and put on a hooded top after bringing a kitchen knife with a six-inch (15-centimetre) blade to school from his home.

Minutes before the attack he dialled emergency services to inform them a teacher at the school would be stabbed.

Imposing a 14-month detention and training order, District Judge Lynne Matthews told the defendant he had acted in a premeditated manner.

"Nothing strikes me about it that was impulsive," she said.

Matthews ordered he serve half the sentence in custody, with the remainder at home working with the area's youth offending team.

The teacher was discharged from hospital on the same day he was attacked and was said to be "recovering well".

- 'Shattered' -

Police in London were on Thursday questioning a 17-year-old boy about the attack on a girl as she made her way to school a day earlier, with the Metropolitan Police naming the victim as Elianne Andam.

She was stabbed in the neck shortly after stepping off a bus in Croydon, south London, as members of the public rushed to try to save her life.

In a statement released through the force, a spokesperson for her family said their hearts were "broken by the senseless death".

"Elianne was the light of our lives," the statement added. "She was only 15, and had her whole life ahead of her, with hopes and dreams for the future.

"All those dreams have now been shattered. Our lives have fallen apart, along with that of our wider family," it said.

UK Prime Minister Rishi Sunak called the death "absolutely shocking" on Thursday.

Police said they were combing security camera footage from the area of the attack, and had spoken to a number of witnesses.

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. Thirteen of those victims 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.