A son brutally killed his father in an attack with scissors and told an emergency services operator: "I'm not bothered."

Derek Main plunged the weapon about 12cm deep into his father Andrew's neck before claiming: "My dad's gone AWOL. He said he did not want to live so he started hitting himself."

Main, who has previous convictions for violent crimes, was originally charged with murdering his 57-year-old father on July 7, 2014, at the victim's home address on Corrie Avenue, Stenhousemuir, in Stirlingshire.

On Wednesday, the Crown accepted his guilty plea to the reduced offence of culpable homicide on the basis of diminished responsibility, when he appeared at the High Court in Edinburgh.

Psychiatrists agreed the 37-year-old's behaviour was substantially impaired because of "abnormality of mind" at the time of the killing.

Main admitted assaulting his father by repeatedly punching, kicking and striking him on the head and body and killing him with a pair of scissors.

The only child also admitted assaulting his father to his severe injury at his home on October 14, 2012, after attacking him with a knife.

The court heard that before the killing, Main was at his father's home where he was drinking. His father was out for the evening with friends and was described as "in good spirits".

After midnight, Andrew Main, a former boxer who worked in the construction industry, got a taxi home from Falkirk town centre and he appeared to be his "usual self and appeared happy".

He later contacted a taxi firm and asked for a cab to come to his home and said the destination was "The Valley" where his son lived, advocate depute Angela Gray said. But eight minutes later, a further call was made by the son asking for a taxi or an ambulance to attend.

The prosecutor said: "During that eight-minute window, between the two calls to the taxi company, we can deduce that the fatal attack on the deceased took place. There are no witnesses to the assault.

"When a taxi turned up at the house the son got in. The driver saw that he had a large amount of blood on his hands and on the areas of his top and trousers, as if he had wiped his bloody hands."

Main was told to get out the cab, which he did, and the driver contacted his call handler who alerted police. He then made his first of two calls to the emergency services asking for an ambulance.

In the calls, he said: "My dad's gone AWOL. He said he didn't want to live so he started hitting himself. I think he's dying, can you hurry up? He's dying. He's locked the front door and being a weirdo."

In a later call he added: "He said he didn't want to live. I am sick of this, I'm not bothered."

Police arrived at the address and found Andrew Main lying on the living room floor, heavily bloodstained, with a stab wound to the neck. Officers attempted to resuscitate him but he died of his injuries.

The court heard that during the previous attack on his father in 2012, a drunk Main struck him with a knife on the body before punching him in the face.

Main then chased his father out into the street before locking the front door of the house while he stayed inside singing football songs.

His father was taken to hospital with wounds to his head, chest and stomach, which were stitched.

After the fatal attack, Main was sent to Carstairs State Hospital and was found to be suffering from psychotic symptoms, including hallucinations and delusions.

The judge told Main that in view of the guilty pleas he had made to the crimes of assault to severe injury and the culpable homicide of his father, and psychiatric reports, he would make an interim compulsion order.

Under the order, Main will be returned to the high-security psychiatric hospital pending a further court appearance.

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