A judge has condemned calls to legalise cannabis after a son killed his estranged mother during a severe mental health episode when he developed paranoid schizophrenia following his habitual smoking of the drug.

Judge Steven Everett warned cannabis was a ‘terrible’ substance which ’caused and exacerbated’ mental health issues.

And he said campaigns to decriminalise it – led by politicians including Labour mayor Sir Sadiq Khan, Liberal Democrat leader Sir Ed Davey and the Green Party’s Zack Polanski – were ‘wholly misconceived.’

The judge hit out after hearing how drifter Simon Carter made a 245 mile trip from his rented room in Devon to batter his widowed mother Gwyneth, 73, to death with such ferocity he broke his own hand.

Just two days before the fatal assault at the elderly victim’s home in Macclesfield, Cheshire, Carter, 50, had admitted himself to a hospital.

He admitted a history of abusing cannabis and claimed he had been attacked by mystery assailants before being forcibly injected with heroin.

But he was allowed back on the streets because doctors had no ‘mechanism’ or proper reason to have him detained. 

He has since been diagnosed with paranoid schizophrenia and having delusional beliefs.

Gwyneth Carter, 73, was battered to death in her own home in Macclesfield, Cheshire, by her estranged son Simon, 50, after cannabis ’caused and exacerbated’ his mental health issues

Judge Steven Everett (pictured) said Gwyneth Carter’s killing was just the latest tragedy to illustrate why calls to decriminalise cannabis were ‘wholly misconceived’

At Chester Crown Court, Carter was ordered to be detained in a secure psychiatric unit having admitted manslaughter on the ground of diminished responsibility.

Judge Everett told him: ‘This is just further evidence as far as I can see that those who talk about cannabis being somewhat of a positive drug in the community are wholly misconceived.

‘You are not the first and sadly won’t be the last with mental health issues to appear before me and say: “I smoke cannabis.”

‘There is a wealth of evidence that use of that terrible drug causes and exacerbates mental health issues.

‘Whatever else it causes it is clear your bizarre behaviour and comments to your doctor were there for all to see. 

‘But there was no reason or mechanism to keep you out of the community when you were seen by the hospital in days leading up to your mother’s death.

‘What was going through your mind is difficult to assess but I am quite sure it was affected by significant mental health issues.

‘You intended to carry out some sort of, as you saw it, wrongly, retribution upon your mother and it appears that you still now have those delusional beliefs.’

Carter had been estranged from his parents since 2006 and was unaware his father Norman had passed away.

Tragedy struck when he decided to pay his family an unexpected visit on the pretext he wanted to see his children.

On July 12, 2025, Carter travelled to Macclesfield where great grandmother Mrs Carter lived alone.

She contacted her sister Janis to say he had arrived ‘out of the blue’, prosecutor Martin Reid KC said.

‘Mrs Carter described the defendant as acting very strangely and she couldn’t work out whether he was drunk or on drugs, and that he just didn’t feel like her son.’

On being told his father had died, she said he ‘did not seem bothered and he only stayed for 10-15 minutes’.

The following day he was admitted to an unnamed health facility where he reported being attacked ‘multiple times’ and injected with heroin whilst living in Torquay.

‘He said he used to smoke cannabis but had stopped a month ago,’ Mr Reid said.

‘He appeared confused, uneasy, talked excessively and asked: “Do you think I’m mad?”

‘But medical examinations revealed no findings and he was discharged.’

Then on July 16 Carter was seen carrying a rucksack containing a saw before loitering outside his mother’s house.

A neighbour heard a ‘lot of banging and shouting’ and heard Mrs Carter pleading ‘No’ and then what sounded like a heavy suitcase being dragged down the stairs.

Her body was found in the living room two days later after her sister – who had been trying in vain to contact her – gained access to the property.

Tests showed she died from multiple head and neck injuries. 

As police investigated, Carter admitted himself to Macclesfield Hospital A&E where he was treated for a broken hand.

Asked about his injury by a nurse, he replied: ‘Oh, I punched something.’ 

He was arrested shortly afterwards as he walked through Macclesfield town centre.

In a victim personal statement Janis Slater said: ‘Gwyneth was just getting back to her usual self after a few years of sadness following the death of Norman.

‘She started to believe that she had a life again. 

‘Then she rang me around tea time on a Saturday and said: “Guess who has turned up after 19 years?”

‘I started to worry about Gwyneth with Simon being around and I told her to lock the doors and windows and hide her jewellery. 

‘There had been issues before he left and Gwyneth said he would not be coming back.

‘I just wish you had told me when he came again. Before you answered the door, I would have been there in five minutes. 

‘I miss you dearly. Our day trips out, our shopping, our meals out, our chats and conversations. 

‘I miss your laughter which was loud and infectious.’

In mitigation, Owen Edwards KC, said Carter’s life had been ‘marred by drug use and significant mental health issues’. 

‘He has fixed ideas as to that which has happened to him and to individuals that he believes are close to him,’ he added.