A 14-year-old girl who admitted manslaughter after a 13-year-old boy was knifed to death has had a custodial sentence increased by appeal judges.

The girl had been given a sentence of three years and two months following the killing of Olly Stephens in Reading, Berkshire, in January 2021.

Three appeal judges on Friday concluded that the sentence was unduly lenient, after Solicitor General Alex Chalk raised concern.

Lady Justice Macur, Mr Justice Picken and Judge Mark Lucraft, who oversaw a Court of Appeal hearing in London, said the term should be increased to five years.

The girl and two teenage boys had been involved in Olly’s death and the boys were convicted of murder after a trial at Reading Crown Court.

The girl was 13 at the time, one boy was 13 and the other boy was 14.

All three were sentenced in September to custody in young offender institutions by Judge Heather Norton.

Olly had been lured to a field near his home, after a dispute on social media, and “ambushed”, judges heard.

The two boys were said to harbour “grievances” with Olly.

One boy who had fought with Olly was given a life sentence with a minimum term of 12 years.

Judge Norton gave the second boy, who had stabbed Olly, a life sentence with a minimum term of 13 years.

The girl had coaxed Olly to Bugs Bottom Field, in Emmer Green, Reading, and had told friends that she was “setting Olly up”, judges heard.

She said she was not aware that anyone had a knife.

Barrister Tom Little QC, who represented Mr Chalk, argued that the girl’s original sentence of three years and two months was unduly lenient.

Kate Lumsdon QC, who represented the girl, disagreed.

Appeal judges decided that Judge Norton had made an error when deciding on the girl’s sentence.

They said the neither the girl nor the two boys could be identified in media reports of the case.