A 14-year-old girl who stabbed her mum’s boyfriend to death had a traumatic childhood and had been permanently excluded from primary school aged eight, an inquiry has now revealed.

The manslaughter, which took place in West Sussex, was a “failure of the system as a whole” the report - a child safeguarding practice review by Birmingham and West Sussex authorities - found.

The girl, referred to as Child A, killed the man, who cannot be named to protect the identity of the teenager, in October 2020 in a part of the county The Argus is choosing not to name. 

Described as "kind and gentle", the man was 24 when he died and was having a relationship with the teenager's mother.

He did not live with the mother and daughter.

Child A had spent most of her life in Birmingham and had only moved to West Sussex in April 2020.

She pleaded guilty to manslaughter due to diminished responsibility in July 2021.

After she had killed her mother’s partner, she said that she saw him as a positive influence in her life.

The report reads: “On the one hand what happened to Adult A is immeasurable because his life was taken, but Child A is more than a perpetrator of a terrible crime.

“She is also a vulnerable child who has been a victim of significant and horrific trauma and abuse in her short life.

It found that the systems put in place to help the child throughout her troubled life had had “no effect at all”.

Child A’s young mother had been a victim of domestic violence before her daughter was even born.

By the time she was eight, she had been permanently excluded from school. Incidents included Child A smothering her half-brother in 2017.

In 2019, she was showing “more and more signs of worrying behaviour”, the report said.

Child A repeatedly went missing, threatened her mother with a knife and was sexually assaulted when she was just 12.

She was remanded to the secure juvenile estate, after she stabbed her mother in the leg and then set fire to her bedroom. On her release she returned to live with her mother.

The report said: “For a child to kill an adult is the rarest phenomenon of all.”

A spokesperson for West Sussex County Council said: “Our sympathies and condolences are with the family and friends of the man who died.

“It is extremely rare for a child to cause the death of an adult, as the report makes clear. While in no way diminishing her actions, the perpetrator was, and remains a child who had experienced trauma and abuse throughout her young life while living in Birmingham.

“We welcome this report which looks at the involvement of multiple agencies, including our children’s services when the child moved to West Sussex, seven months before the incident. Our involvement included regular, face-to-face contact from our staff during the Covid-19 pandemic. As the report acknowledges, our staff who supported her and recognised the huge trauma she had suffered and the impact this has had on her life.”

Child A remains in the custody of the secure estate and is receiving treatment after she pleaded guilty to manslaughter on the grounds of diminished responsibility.