The Attorney General’s bid to change the sentence of Valdo Calocane is set to be considered by the Court of Appeal.

Calocane was given an indefinite hospital order for the manslaughter by reason of diminished responsibility of Barnaby Webber, Grace O’Malley-Kumar and Ian Coates, and the attempted murder of three others in Nottingham last June.

The 32-year-old’s pleas were accepted by prosecutors in January after medical evidence showed he has paranoid schizophrenia.

Attorney General Victoria Prentis referred the sentence to the Court of Appeal in February, claiming it was “unduly lenient”.

Calocane fatally stabbed 19-year-old university students Mr Webber and Ms O’Malley-Kumar as they walked home from a night out in the early hours of June 13 last year, before killing Mr Coates and stealing his van.

He used the vehicle to knock down three pedestrians – Wayne Birkett, Marcin Gawronski and Sharon Miller – in Nottingham city centre before being arrested.

The sentencing judge, Mr Justice Turner, told Calocane at the city’s crown court that his “sickening crimes” meant he would likely be detained indefinitely in a high-security hospital “very probably for the rest of your life”.

He also ruled that Calocane should be subject to further restrictions if ever discharged from hospital, which would need to be approved by the Justice Secretary or a Mental Health Tribunal.

Barristers for the Attorney General’s Office (AGO) are expected to argue on Wednesday that Calocane should instead be given a “hybrid” order, meaning he would be treated in hospital before being transferred to a regular prison to serve the remainder of his sentence.

If judges agree, they will set the length of time that Calocane must serve for the offences, with his release then governed by the Parole Board.

The families of the victims have previously criticised Calocane’s sentence, with Mr Webber’s mother, Emma, claiming in January that “true justice has not been served”.

She said: “We were presented with a fait accompli that the decision had been made to accept manslaughter charges.

“At no point during the previous five-and-a-half-months were we given any indication that this could conclude in anything other than murder.

“We trusted in our system, foolishly as it turns out.

“We do not dispute that the murderer is mentally unwell and has been for a number of years.

“However the pre-mediated planning, the collection of lethal weapons, hiding in the shadows and brutality of the attacks are that of an individual who knew exactly what he was doing. He knew entirely that it was wrong but he did it anyway.”

The hearing before the Lady Chief Justice Baroness Carr, Lord Justice Edis and Mr Justice Garnham is due to start at 10.30am on Wednesday at the Royal Courts of Justice.