Eddie Ratcliffe, one of two teenagers convicted of the murder of 16-year-old Brianna Ghey, has had a bid to challenge the length of his sentence dismissed at the Court of Appeal.

Brianna was stabbed 28 times with a hunting knife during the fatal attack by Ratcliffe and co-defendant Scarlett Jenkinson in Linear Park, Culcheth, near Warrington, in February last year.

Ratcliffe, who was 15 at the time of the killing, was sentenced to life with a minimum term of 20 years in February this year, with a judge describing the murder as “exceptionally brutal” and finding that he had expressed transphobia about his victim.

Brianna Ghey was stabbed several times in a park in Culcheth (Family handout/Cheshire Police/PA)

At a hearing in London, lawyers for Ratcliffe, who is now 17 and has been diagnosed with autism spectrum disorder and selective mutism, said the sentencing judge, Mrs Justice Yip, had failed to take into account his “immaturity” and that the minimum term was “far too high”.

The Crown Prosecution Service opposed the appeal bid, claiming that the sentence was “appropriate” and was not “manifestly excessive”.

In a ruling on Thursday, three senior judges dismissed the bid, finding that arguments made in favour of reducing Ratcliffe’s sentence were “based on a false premise”.

Summarising their judgment, the Lady Chief Justice Baroness Carr, sitting with Mr Justice Lavender and Mr Justice Murray, said: “The judge’s choice of a starting point of 20 years for a minimum term was correct, for the reasons that she gave.

“The judge was then entitled to take into account the aggravating factors as identified.”

She continued: “The sentence imposed by the judge on the applicant was neither manifestly excessive, nor wrong in principle. The proposed grounds (of appeal) are not arguable.”

Ratcliffe, who attended the hearing in London via a video link dressed in a dark suit, shirt and tie, showed no emotion as the appeal bid was dismissed, with his mother present in court.

The court also heard that Brianna’s family were in attendance remotely.

Richard Littler KC, for Ratcliffe, earlier told the court that his sentence was “wrongly and artificially elevated” and was “far too high”, adding that the judge had failed to take into account his age and maturity.

He said: “It is right to say that on any analysis of the applicant’s maturity, he is closer to the starting point of a 14-year-old rather than a 17-year-old boy.”

He added: “The point we make is (that) age and maturity were very important issues in this case, and could very much affect the end result for this particular applicant.”

Mr Littler said that Ratcliffe was found to have “poor social skills” and “immaturity”, as well as “a lower-than-expected ability to express what he thinks or articulate his ideas”.

He said: “There is no doubt they were taken into account, but they were not taken into account fully.”

Deanna Heer KC, for the CPS, said that Ratcliffe’s attitude towards Brianna was “dehumanising” and that the killing involved “sadistic conduct”, adding that the sentence was not “manifestly excessive”.

She continued that the minimum term was “appropriate… on the evidence in the case”, and that Ratcliffe’s autism diagnosis “did not prevent him from understanding what he was doing”.

She said: “Eddie demonstrated himself throughout to be just as enthusiastic about what they were going to do as Scarlett.”