Rick Parker, 40, called the ambulance service after the alleged slaying and calmly told them his mother Helen Harrison - who was lying battered and bloodied in the vestibule at their three- bedroom home in Market Weighton - was dead, Hull Crown Court was told.

Parker told the operator it was “definitely a body-bag job” and when police and an ambulance crew arrived at the rural property and asked him where the weapon was, he told them: “In her shoulder.”

The prosecution alleges that Parker strangled his mother and stabbed her in the head and chest with a 20-inch kitchen knife.

Her husband had already moved out of the property after being physically assaulted by his stepson despite being in his 70s, and was scared to return there.

Prosecutor Geraldine Kelly said Mrs Harrison was bleeding heavily from the head and chest and there were blood spatters all over the wall, door and surfaces of the hallway when she was found by officers and paramedics.

It’s believed that Parker, who had developed mental health issues following a road accident, killed his mother, with whom he lived, because she wanted him to leave the house and get help for his problems.

On March 5 last year, a Sunday, Mrs Harrison had called the ambulance service asking them to take her son to hospital so he could get the help he needed. But when paramedics arrived, it was Parker who answered the door.

When the two paramedics asked to speak to his mother confidentially, she told them she couldn’t “because he would lock her out”.

The paramedics said they couldn’t take Parker to hospital if he didn’t consent and drove away, only to receive a call from the ambulance service about 20 minutes later telling them to go back whence they came because there was a life-threatening situation at the home in Aspen Close.

They headed back towards the house and found Parker in the garden at the side of the house, seemingly unperturbed and directing them to the hallway where his mother lay dead.

The prosecution also alleges that Parker beat up his stepfather Roy Thompson at the Aspen Close property on February 19 last year, just two weeks before his wife Mrs Harrison was killed.

Parker is alleged to have headbutted and punched the elderly man, causing injuries head injuries.

He was charged with murdering his mother and assaulting his stepfather, causing actual bodily harm, but was deemed unfit to plead by the court on the recommendation of medical professionals. It means he will not be required to attend throughout the finding of fact proceedings, which will be

decided by a jury but not in a conventional trial because no pleas have been entered by the accused.

Instead, they will be asked to decide whether Parker did the acts alleged or is not guilty in his absence.

Ms Kelly said Parker punched and headbutted Mr Thompson, then aged 72, in an unprovoked attack, which left him with two black eyes, bruising and a cut to his nose and head, just over two weeks before he killed his own mother with a kitchen knife.

A post-mortem revealed Mrs Harrison died of a stab wound to the chest combined with strangulation. She had suffered a “significant neck injury typical of strangulation which would have led to an unconscious state”. The stab wound had gone through her chest and penetrated her windpipe and main artery.

The pathologist said there were also “blunt-force injuries to her head consistent with blows being struck”.

Ms Kelly said that Mrs Harrison, a mother-of-two, and Mr Thompson had been together for about 13 years at the time of her death.

In 2021, Parker moved in with them at the property in Aspen Close and the atmosphere inside the house was convivial for a while, but things changed after he was knocked off his bike and suffered spinal injuries in a road crash in Holme-on-Spalding-Moor in December of that year.

“He stopped working and it seemed his mental health went into decline,” said Ms Kelly.

“Roy Thompson…noticed a difference in his behaviour. (Parker) seemed to lock himself away in his bedroom.

“Mr Thompson noticed towards the last couple of months before Helen Harrison’s death that (Parker) was pacing up and down, talking to himself and laughing.

“Mrs Harrison asked her son if he needed help but (Parker) wouldn’t accept help. In the week leading up to her death, Mrs Harrison wanted her son to leave their home.

“Roy Thompson and Rick Parker weren’t getting along in that time and Helen Harrison was aware of that friction.”

She said that Parker and Mr Thompson had fallen out over a leak in the loft which had caused a damp patch in the hallway.

“Rick Parker was annoyed with Mr Thompson for not sorting it out and (there was) tension about Mr Parker no longer contributing to the household finances because he was no longer working,” added Ms Kelly.

She said this culminated in the attack on Mr Thompson in the living room on February 19 after he and his wife had a “bit of a tiff” because Mrs Harrison was still “a bit upset about (her son) still living there”.

“Mrs Harrison and Mr Thompson were both in the living room when Mr Parker came into the room and (affectionately) put his arm around his mother,” said Ms Kelly.

“Mr Thompson was lying on the sofa. As (he) looked over to see how Mrs Harrison was, Rick Parker said to him, ‘What are you looking at?’.

Parker then “jumped on (Mr Thompson) and, kneeling on him, punched him a couple of times in the head, causing a large bruise”.

He then headbutted him in the nose which “pushed Mr Thompson’s glasses into his face”.

As Mr Thomson was bleeding from his head and nose, Parker told him: “If you ever raise your voice at my mother, I’ll take you outside and drag you over that step and beat you to death.”

Four days later, Mr Thompson’s children from a previous relationship called police about the alleged attack after noticing bruises and cuts to his head.

He moved out of the house after the incident “because he feared for his own safety”. He moved in with a friend where he remained until his wife’s death in March.

On the day in question, Mrs Harrison and her husband had visited a garden centre and been out for lunch before returning to Mr Thompson’s friend’s house.

“Later on, she planned to see her son at Aspen Close…and the reason for that was to see if she could persuade him to get help for his mental health issues,” said Ms Kelly.

“She called for an ambulance to try to get assistance for (Parker) and in the call she explained she had been advised by police to call for an ambulance for a mental-health assessment.

“She said that he had severe mental-health problems, but he wouldn’t get any help (and that) he had attacked her husband.”

She told the ambulance service that her son had been “whispering to himself…and didn’t seem to be in touch with reality”. A mental health crisis team had referred him back to his GP.

In anticipation of the ambulance arriving to pick up her son, Mrs Harrison told her husband she would return to Aspen Close, but he said he was too afraid to go into the house because he was fearful of being attacked again.

Ultimately, Mr Thompson agreed to drive his wife to Market Weighton and dropped her off near the house. He waited in the car until she returned with his work clothes.

She gave her husband a kiss and said she would ring him later to tell him how she got on with her son, “but they were the last words he would (ever) hear from her”.

“She returned to (the house) to await the ambulance and her plan was to tell (her son) that he had to be out of the house by (the following) Friday dinnertime, when she (would be leaving) for work,” said Ms Kelly.

Two paramedics arrived at about 4pm and Parker answered the door. He calmly asked them what they wanted and when they said they were there to get him help, he said he “didn’t need their help”.

They said that Parker seemed “calm” but when his mother came to the door she appeared “slightly agitated and wanted to tell them what had been going on”.

When one of the paramedics asked Mrs Harrison if she wanted to come over to the ambulance for a quiet chat, she said that if she left the house “he’ll lock me out”.

One of them told her that her son appeared to have “full (mental) capacity” and that they “couldn’t force him to do anything he didn’t want to do without consent”.

“They said they were sorry: there wasn’t anything they could do, and they left,” added Ms Kelly. Ms Kelly said it must have been “very soon after that…that Rick Parker…killed his mother” because her neighbours James and Helen Cox heard screams as they walked past the house moments later.

Mrs Cox heard “a noise she described as (like a) child or someone having a tantrum”, said Ms Kelly. “There were no words, just loud screaming, (followed by) what appeared to be kicking at the (front) door” which was ajar. As Mr and Mrs Cox walked up to the house, the screaming stopped and it “went quiet”.

“They heard nothing more and they didn’t know what to do, so they walked away from the address and left the area,” said Ms Kelly.

“In fact, Helen Harrison was later found lying in her hallway, stabbed, face down with her head towards that front door.”

Within minutes of the couple hearing “what seemed like a violent struggle” and the paramedics departing, Parker called the ambulance service to say there had been an accident and that his mother was dead.

About 20 minutes after the alleged slaying, the same paramedics received a call from the ambulance service saying there was a life-threatening incident at the house in Aspen Close they had just left.

Parker had told the operator that a woman was “badly injured” and “clearly dead”, said Ms Kelly.

He said it wasn’t a “desperate hurry” but “I suppose someone will have to come down”.

When the operator asked Parker to try chest compressions to resuscitate the woman, he said “it wouldn’t help”, adding: “It’s definitely a body-bag job”.

The two paramedics arrived back at the house with police at about 4.50pm and found Parker at the side of the house. When they asked him where the knife was, he replied: “In her shoulder.”

“He didn’t seem to be in any rush when asked if his mother was okay,” added Ms Kelly.

“He said, ‘she is (okay) now’”.

Parker was sat on a garden chair when police arrived and told them calmly that his mother was in the hallway. Her body was found dead in the vestibule, with the knife protruding from her right shoulder.

Ms Kelly said that Mrs Harrison, who was a keen swimmer and enjoyed horticulture, had suffered “catastrophic bleeding”.

Following his arrest on suspicion of murder, Parker told officers: “I understand. I was expecting a lot coming to me at 40 (years of age).”

A scene-of-crime officer said he believed the attack started in the kitchen where tables and chairs had been disturbed and “items knocked from the fridge”.

It appeared that Mrs Harrison had spilled a drink and had then gone to ground near the front door of the hallway.

He said that Parker had washed his blood-stained hands in the kitchen sink after the alleged murder. Mr Thompson, who married Mrs Harrison in 2012, said Parker’s personality and behaviour seemed to change after the road accident.

He said they had got on initially, but tensions arose when Parker was unable to pay his board following the accident which resulted in him losing his job at Howdens, the local kitchen supplier.

He said there were no “raised voices” when he and his wife had a “little tiff” before Parker attacked him.

The finding of fact hearing continues.

Helen Harrison was also a member of a local steampunk Morris dancing group, Ravens Morris, who described her as ‘one of the family’.

Helen Harrison murder: Keen swimmer and dancer, 59, 'stabbed to death by her son' in Yorkshire market town after she had tried to seek medical help for him