A TEENAGE rapist who tried to kill two Bracknell schoolgirls will spend life behind bars after his sentence was increased on appeal today.

Callum Stroomer has had his 'unduly lenient' sentence of 17 years for the violent attempted murder of two 15-year-old girls at a Bracknell home increased to life with a minimum of 13 years by the Court of Appeal today.

The 18-year-old was on bail for the rape and sexual assault of two other teens when he stabbed the school girls in March 2015, leaving both with life-changing injuries and one left fighting for her life.

The Solicitor General, Robert Buckland QC MP, referred the sentence to the Court of Appeal and personally presented the case at today’s hearing.

He said: "I referred the original sentence as I felt that it did not properly reflect the severity of the case. The offences included the vicious attempted killing of two girls in a violent knife attack, as well as serious rape and sexual assault in circumstances of blackmail.

"I hope this increased sentence gives some comfort to the victims and their families."

Stroomer, of Dee Road in Tilehurst, Reading, was originally sentenced at Reading Crown Court on October 23, 2015 following a two-week trial at the same court in September.

His extended 17 year sentence included a three and a half year jail term for a string of sexual offences committed against a further two young girls in 2014, including two counts of rape, which he admitted in May 2015.

A psychiatric report found Stroomer showed 'no victim empathy or remorse' and that he presents a future risk of harm to others.

When passing a life sentence a judge must specify a minimum term, the length of time an offender must spend in prison before becoming eligible to apply for parole.