A man has pleaded guilty to the manslaughter of his grandmother after starting a fire at her Norwich home.

Chanatorn Croghan, 19, of Northside in Norwich, has admitted setting the blaze that killed 89-year-old Vera Croghan in her home on Unthank Road on December 11 2020.

Norwich Crown Court heard on Thursday that his guilty pleas to arson and manslaughter due to diminished responsibility that were submitted last September were now accepted by the prosecution following psychiatric reports.

Will Carter, prosecuting, said reports from three separate psychiatrists had all agreed he was suffering from diminished responsibility due his mental condition.

One report had found he had a “psychotic disorder secondary to multiple substance abuse issues”, he added.

The teenager, who had been accused of the murder of his grandmother and attempted murder of his father in the fire, had refused to to appear before the court on a videolink from Norwich prison where he is on remand.

Croghan, who is also known as Marco, was staying with his grandmother when police were called to the address at around midnight on December 10, 2020 following an argument between him and another man.

On arrival officers established no offences had taken place and he stayed at his grandmother’s house and the man left without Croghan’s knowledge.

At around 6.30am the following morning, a member of the public called 999 after seeing smoke coming from the home.

Firefighters discovered a blaze had been smouldering for some time and found Mrs Croghan in an upstairs bedroom. She was pronounced dead at the scene.

A Home Office post mortem later established she had died from the result of smoke inhalation.

Croghan returned to the property later that day and was arrested. He was later detained under the mental health act for observation and treatment.

Mr Carter said a meeting had taken place with family members to explain the prosecution decision to accept a plea of manslaughter due to diminished responsibility.

Croghan will appear at Norwich Crown Court for sentencing on April 14.

Judge Anthony Bate said the case was “very sensitive and troubling”.

He ordered a further report into Croghan “degree of retained responsibility and risk of harm to the public” prior to his sentencing.