The passing years have obliterated the full terror of it, but there are images that come back to haunt Gemma Ahern, like snapshots from a horror film.

Gemma, now 36, was just three years old when her father killed her mother – stabbing her 36 times with her dressmaking scissors – while their young daughter ate her breakfast downstairs at their little mews house in Greater Manchester in 1992.

'I don't have any memories of Mum before Dad killed her. I only remember seeing her slumped down by the side of the bed,' says Gemma.

'What I know now is that Dad stabbed her; for the first time with a small kitchen knife which snapped, and that's when he came downstairs. I heard him frantically rooting around in the kitchen.

'I've learned since that a neighbour heard Mum shout from the bedroom window, "He's trying to murder me". But the neighbour didn't want to interfere. She did nothing.

'Mum loved dressmaking and she had these long, heavy shears. Dad stabbed her 11 times in her heart and 25 more times.'

It was, by anyone's assessment, a frenzied and sustained assault, and laceration marks on her arms showed that Gemma's mum – then 26 – had tried to fend off the onslaught.

Court reports claim that Gemma was downstairs watching TV during the attack, but she says she has fragments of memory from the aftermath. 'I saw blood everywhere. I don't know what I said to Mum but I was trying to look for signs of life. There were none.'

Gemma's recollections – scant though they are – are harrowing. But what happened next only compounded her trauma.

After the fatal stabbing, her father, then 27, was found guilty of the lesser charge of manslaughter rather than murder.

Judge Mrs Justice Smith sentenced him to four years. She accepted the defence's claim that his actions were out of character, saying he seemed to be a decent young man, according to local newspaper reports from the time.

Then, on his release after just two-and-a-half years, Gemma was placed back in his care. It sounds unthinkable, but she went to live with her dad again – soon gaining a step-mum and step-sister, then a half-brother – and life moved on.

It was as if her mother had never existed and her brutal death at her father's hands was merely a ripple. He discouraged Gemma from speaking about the fact he had killed her mum, even casting himself as the victim. 

'He blamed Mum because she'd been seeing another man,' she says. 'My childhood was entirely focused on Dad's wellbeing and happiness. Nobody ever considered mine.

'Dad killed Mum in the most horrific way and I was just handed back to him after he'd served little more than half of a four-year prison sentence. Mum was erased from my memory. I willed myself not to ask about her because Dad made it clear he didn't want me to.

'Everyone in my sphere normalised Mum's killing. My dad was very clever at making me believe it had all been her fault. He'd want us to feel sorry for him. The story was,

'Poor man, he was pushed to the limit and this happened'.

'He cried in court and even the judge said, "I can see how remorseful you are". But he has never shown an ounce of remorse to me.'

Neither was there any special care for the traumatised child. Gemma was forced to suppress her grief.

'Social Services were not informed about me. They had no record of me. I wasn't assigned a care worker. I had no support at school.

'As I got older, I was very ashamed of what my father had done, that he'd been to prison – but now I know it was not my shame to carry.

'And the staggering thing is, it's still happening. Children are still living with one parent who killed another. What's more, there's nothing – no register or record of who they are – in place to help them.'

Estimates of how many such children there are in the UK today living with a parent who killed another vary between 50 and 200 and, despite the scale of their trauma, there is no consistent system in place to identify them or ensure they receive the support they need.

Contemporary newspaper reports fuelled the moral outrage against Gemma's mum. 'The stories were diabolical, the bias horrible. They said Mum was an unfaithful wife, when the marriage was already breaking up. I later discovered that Mum had put her name down for a council house, so she could take me to live away from Dad.'

Gemma has also since learned that her dad could be emotionally controlling and bullied her mother about her weight.

Today, softly-spoken with long ink-black hair, Gemma talks to me from the refuge of her calm, plant-filled kitchen in North Wales. She lives there – now estranged from her father and his side of the family – with her son and partner.

A yoga teacher who specialises in the effects of trauma on the body, she runs her own studio. She also campaigns alongside the charity Children Heard and Seen, which aims to give a voice to the forgotten children who experienced the death of one parent at the other's hands.

She is speaking out now to help these forgotten children, and will join an advisory group of adults meeting at Westminster next week to help shape better support for children affected by domestic homicide. She is also urging for the swift implementation of Jade's Law, named after Jade Ward who was murdered by her ex partner Russell Marsh in 2021. Marsh then went on to seek contact with their children from prison.

Jade's Law will prevent this and bar such killers from securing custody of their kids after their release.

After the killing, Gemma's dad turned himself in, taking his little daughter to the police station with him and saying he had no memory of the attack.

In court, he broke down sobbing when asked to look at a photograph of his wife's body and admitted manslaughter on the grounds of 'provocation'. 'I don't want to see it – it's my wife,' he cried in the witness box.

Perhaps this, coupled with his apparent remorse and the suggestion that it was a 'crime of passion', after he became suspicious when he found a card with a man's name on in her bag, all contributed to the decision not to convict him of murder.

Sustained campaigning by women's groups over the past three decades means domestic violence is now seen as a serious crime rather than a 'private' issue.

For a few months, Gemma stayed with her maternal grandparents. Her memories are hazy but her grandmother remembers her distress: 'She has told me she found me sitting on the stairs one night, crying and asking for my mummy.

'She hugged me and said, "I know where your mummy is". She took me to the window and said, "Find the star that is blinking the brightest". I found it and she said, "That is your mummy, winking at you", and I just accepted that Mum was there.'

There were other intimations that she was unsettled by her mother's violent death: 'Grandma said she once found me punching a pillow. Then, when she was cutting beetroot I backed away, thinking it was blood.'

Set against this, happy images stay with her: their garden, a paddling pool; her grandfather dressing as a clown to entertain her friends at tea parties; playing with her grandparents' beloved dogs.

But these transient, settled months came to an abrupt end when her dad wrote to his parents from prison, insisting Gemma live with them: 'He was worried that my maternal grandparents would tell me what he'd done, so he told his parents: 'You must get Gemma. It's important that she doesn't stay with them.'

'And children are forced to accept what is presented to them.'

Gemma was sent to live on the other side of Manchester with her paternal grandparents, in Denton.

Regular visits to her dad in prison became part of her childhood routine. She was told he was 'at work' there and accepted the fiction: 'I was excited to visit him. I'd take a cuddly toy and the guards would put it through the scanner.

'Dad would call me. He'd say, 'Listen out at 6pm. You can answer the phone if you want.'

'Towards the end of his sentence he'd come home at weekends. We'd go shopping; he'd buy me toys.

'Then Nana and Grandad took me on holiday and when we came home they had a surprise for me. There was Dad.

'I now know he'd been released. I remember rushing to him and giving him a hug. He shared my bedroom and we had bunkbeds.

'He had different girlfriends he'd introduce to me.'

When she was six or seven her father met the woman who became her step-mother. It was the start of fresh upheaval – they moved into her home, with her daughter – and the onset of new misery: her step-mother conformed to the stereotype.

'She would scowl at me. She never hugged me. When I started my period I didn't tell her or my dad. As an adult I can see that I was an unpleasant reminder of Dad's past.

'He'd told her he'd killed Mum, but – as I did until very recently – she would have assumed he'd just stabbed her once, not 36 times.'

Throughout it all, Gemma buried her loss. 'I made Mother's Day cards at school but had no one to give them to. I'd cry sometimes, quietly at home, but I didn't say a word about Mum. I just got on with life.'

She started high school, told a few friends that her dad had been to prison for killing her mum and found herself the butt of derision and bullying.

'Word got round and I was taunted, beaten up, chased by a group of girls.'

With no responsible adult to confide in she carried a burden of guilt and shame.

Even the comfort of an association with her maternal grandparents was denied to her: 'Dad ridiculed them. He stopped me going to see them. Now I know how much anguish they went through for decades.'

Her father was a successful man. He ran the family engineering company, which prospered: their homes were upgraded. Eventually, they lived in a smart house and enjoyed regular holidays.

'But Dad was never emotionally available. He was always abroad, travelling for work. He never said, 'I love you'. He could also be bad-tempered.

'My step-mum would tell on me if I did something wrong.

'Dad would say he provided everything: holidays to Disney World, fancy new trainers – and there were happy times.

'But I could never mention Mum. Once Dad was telling me off and I said, 'I want my mum' and he ignored me.'

When her half-brother was born, she recalls her step-

mother's delight: 'He was her son with my dad and I realised how loving she could be.

'I was a teen then. I thought: 'Why don't I deserve that love?' I started to see how differently from me he was treated and, though I loved having a brother, the contrast was stark and hurtful.'

After school, Gemma was persuaded by her father to join the family business: 'He was very clever at luring me in. He said, 'Look what I have. You could have that too'. It was about material wealth.

'He was controlling me; emotionally and financially.'

For 17 years she worked with her father, running the accounts department. Still she had not grieved for her mother.

'I didn't even know her birthday, who she was, where her ashes were scattered.'

So what changed?

Three years ago, Gemma began a new relationship with her current partner and moved away from the orbit of her father, to a new home, new job, and a new life in North Wales.

'Dad started to become paranoid about me being away. All the years I'd been linked to him, he felt in control of what I knew about Mum.

'And it was then that the veil started to lift and I began to question the information Dad had given me.'

Gemma's search for the missing pieces of the jigsaw that made up her mother's life – and death – was exhaustive.

'And the more I found out, the more horrified I became.

'It was only when I researched in newspaper cuttings from the time of Dad's trial that I discovered he had stabbed her 36 times. Before that, I'd assumed it was once: one terrible, fatal mistake because Mum had been winding him up.

'But now I realised how he'd minimised it; how violent and inhumane he'd been, and I wanted to ask him how he'd got to the point where he'd stabbed her so many times.

'I felt sick, angry. I rang him up and screamed at him. He was horrified and still tried to make excuses. He told me my mum never wanted me, that she didn't love me. He asked why I was making such a big deal about it when my mum hadn't been a good mother.

'In that moment I lost my dad. I didn't want anything more to do with him. It was both liberating and scary, because I knew in cutting free from him I'd also lose all his side of the family.

'It was hard to come to terms with and I realise now that for the first time I started to grieve. I cried and cried for Mum. I'd slipped through the net when I was a child, but this time I got help from Victim Support. I've also had a lot of therapy.'

She was diagnosed with Post Traumatic Stress Disorder (PTSD) and Attention Deficit Disorder (ADD) – trauma can be linked to ADD.

'I also wanted to find out about Mum, to reclaim her voice, her story; the truth. So I put a post on social media and got more than 100 messages, all saying how lovely she was.'

Through this, she met her mum's best friend Joanne: 'Mum had been her friend since childhood and chief bridesmaid at her wedding.

'We met in a park where they used to go as teenagers and listen to their transistor radio.

'Joanne gave me a photo of Mum, vibrant and laughing; so beautiful in her coral pink bridesmaid's dress. She told me Mum was full of fun and mischief, that she loved music, dancing and sewing. She made my clothes, curtains, bedding – she was house proud – and Joanne said Mum had been desperate for a daughter. I know now I was her world.

'The meeting helped me in ways I didn't realise I needed. I was able to ask questions about Mum I'd kept inside for so long, about our lives before she was taken from me.'

Gemma also renewed links – severed by her dad – with her maternal grandparents. Her grandfather now has dementia but she is close, once again, to her grandmother.

'It is like a cloud being lifted and I have a great sense of freedom – but it comes at a cost, because the truth is worse than I ever imagined,' she says.

'It is why I believe so strongly that parental rights should be taken from anyone who has killed a parent, and people like me should know that their voice, and the truth, matters.'

Children Heard and Seen supports kids with parents in prison. For details on the advisory group meeting in Westminster on April 21, contact the charity via its website: childrenheardandseen.co.uk. Participants may remain anonymous.