Aaron Campbell, the teenager who abducted, raped and murdered six-year-old Alesha MacPhail on the Isle of Bute last July, has been granted leave to appeal against his 27-year prison sentence.

The Scottish Courts and Tribunals Service confirmed on Tuesday that the appeal would be heard later this summer.

Campbell was sentenced to life imprisonment with a minimum term of 27 years – the longest term set for an individual under the age of 21 in more than a decade – after he was found guilty following a two-week trial in February.

Tributes to Alesha MacPhail left in Rothesay on the Isle of Bute. Photograph: Jeff J Mitchell/Getty Images

Campbell, who was 16 at the time of his arrest and trial, denied any involvement in the offences during his trial but admitted to his crimes when interviewed for psychological reports prepared before his sentencing.

Setting the term of 27 years, Lord Matthews said the reports “had painted a clear picture of a cold, callous, calculating, remorseless and dangerous individual”.

During the trial, the jury heard that Campbell took Alesha from her bed in the seafront flat where she was staying with her father and grandparents, using a knife to silence her, and carried the child to the nearby grounds of a disused hotel where he raped and smothered her.

Alesha, from Airdrie in North Lanarkshire, had arrived on the island a few days earlier for a three-week summer break.

The pathologist who examined Alesha’s body told the court the girl had sustained “catastrophic” injuries, some of which he concluded had been inflicted while she was still alive.

The appeal will be heard by three judges in Edinburgh on 7 August.