A 41-YEAR-Old Lydney woman who was found not guilty of the attempted murder of her neighbour by a jury is to remain in prison due to her mental condition.

Prosecutor Edd Hetherington explained that Joanna Mammatt had stabbed her neighbour four times with a large kitchen knife after breaking into her property during the early hours of May 28, last year.

Ms Mammatt was additionally charged with possessing a knife in public on the same occasion.

The prosecutor explained this was an unusual and sad case and told the jury of nine men and three women, that unusually they had a third verdict option aside from guilty or not guilty - that of not guilty due to insanity.

Judge Ian Lawrie KC told the jury after they had returned their verdict of not guilty by reason of insanity after seven hours and 11 minutes, that Ms Mammatt would be remanded in custody until a date to be fixed, at which a hospital order can be made.

The judge explained that this means that Mammatt will remain under the jurisdiction of the mental health team until such time specialists feel that she is safe to be released. 

Mr Hetherington told the jury that Ms Mammatt had known her neighbour Hannah Gwynn for around two years after Ms Gwynn had moved into an address close to Highfield Road during 2021. 

“In the weeks before this incident Ms Gwynn noticed a decline in Ms Mammatt’s mental health during the brief neighbourly chats that they had been having,” said Mr Hetherington. 

“Ms Mammatt began saying odd things and believed that Ms Gwynn had been placed next door so she and her partner could spy on her.

“Ms Mammatt told Ms Gwynn she knew there were secret recording devices in her shed and that a shadowy group was trying to harm her.”

Ms Gwynn - who is a serving police officer - became so concerned about her neighbour’s welfare that she reported that matter to relevant bodies as well as raising her concerns with her sergeant at work.

The jury heard that Ms Gwynn did not consider Ms Mammatt to be a threat to others, but felt she needed some mental health support. Ms Mammatt was subsequently visited by the police and social services who offered her support over the coming days.

The court heard from Ms Gwynn who gave evidence at the trial. She explained that she had been woken up at just before 4am on May 28, last year when she heard the noise of her front gate closing. She initially thought her partner was returning home early after working a late shift. 

Ms Gwynn said: “I got out of bed, and opened the bedroom door and headed downstairs with my dogs following me. As I got towards the bottom I saw the outline of somebody dressed all in black. I initially thought it was a man, until a woman starting screaming at me. I recognised the voice straight away as my neighbour. I noticed she had a knife in her hand and almost immediately Ms Mammatt began plunging the knife into my leg whilst continuing to scream at me. She accused me of trying to cause her family harm.

“During a short scuffle I grabbed hold of her wrist and I began screaming at the top of my voice in the hope that somebody could hear me. I shouted, ‘Help, help, call the police’. Ms Mammatt was also screaming and I tried to wrestle her towards the front door. I managed to open the door with my keys at the same time I grabbed hold of the knife and threw it as far as I could within the house.

“On opening the door Lizzy Powell, another neighbour, who had heard the commotion, and was outside having already called the police, was able to pull Ms Mammatt out of the property while Ms Gwyn told her that she had been stabbed.”

The jury heard that when Ms Gwynn went back inside her home, in an attempt to find a pair of handcuffs to restrain Ms Mammatt, she realised when she switched on the light that the floor was awash with blood as were her legs. 

“I thought I was going to die,” Ms Gwynn said, as she saw the blood gushing out of her leg.

Another neighbour Marion Balam, who had also assisted in restraining Ms Mammatt, helped Ms Gwynn by putting pressure on her leg to stem the bleeding, while they waited for an ambulance to arrive.

The jury heard that Ms Mammatt had climbed into Ms Gwynn’s house through a downstairs window, having forced it open. When the police arrived at the scene, Ms Mammatt was outside her own home and had been spotted putting clothes into her bin. She told the officers she would accompany them peacefully. 

After her arrest Ms Mammatt told officers she was glad she had done something that would eventually go to court, adding: “I need to tell people what’s happened. I didn’t want to have to do that.”

The jury heard that a blackboard inside Ms Mammatt’s house had various statements wirtten on it, including, ‘If you profess to love God, why you killing her?’ and ‘If I die, life itself dies. I don’t want death to win’. 

On scraps of paper Ms Mammatt had written, ‘Joanna is good, very very good. Hannah, next door, is evil, very evil’ and ‘I’m a friendly giant, she is cruel and must be destroyed’. 

Another sheet of paper had another statement, ‘No evil allowed. Everything is private, including me. I turn Hannah off. She gets no enjoyment from hurting me’. 

Mr Hethrington concluded by telling the jury that it was obvious that when Ms Mammatt tried to kill Ms Gwynn, she was suffering from a very significant mental illness.

Stephen Donnelly, defending, told the jury that his client would not be giving evidence at the trial due to her medical condition. He emphasised during his summing up: “The issues in this case revolve around the mental health issues of Ms Mammatt, which run parallel with the facts. 

“In relation to the main charge, the defence case is the actions of Ms Mammatt did not amount to attempted murder of Ms Gwynn. The psychiatric evidence is such that the defence would invite the jury to return the special verdict of not guilty by reason of insanity. 

“Even if she did have a knife in her possession without good reason, the defence in light of psychiatric evidence, as this was part of her insanity.”

Ms Mammatt was flanked by three mental health support workers in the dock throughout the seven day trial.