The death of a teenager who took her own life in prison could have been prevented, says her family.

On Friday, an inquest jury in Warrington concluded that Annelise Sanderson, 18, died from suicide and noted there were some failings in her care.

But Victoria Davies, area coroner for Cheshire, said she would not be writing a report to prevent future deaths after she felt reassured the various organisations involved had introduced new processes and “tightened up” existing procedures.

Miss Sanderson was sentenced in June 2020 to 52 weeks in custody after she assaulted a paramedic who went to her aid when she tried to set herself on fire at a petrol station.

Six months later on December 22 Miss Sanderson was pronounced dead in her cell at HMP Styal only weeks before she was due to be released.

A safety plan was put in place three days into her custodial term when she was identified as at risk of suicide or self-harm when she was observed with a ligature in her cell.

Miss Sanderson, who also had alcohol and drug issues, was recorded as displaying “bizarre behaviour” when she arrived on June 26 at HMP Styal when strict Covid-19 restrictions were in place.

The plan was closed eight days later after it was noted that Miss Sanderson appeared “settled”, the court heard.

Mental health nurses noted she “engaged very, very well” at her first proper face-to-face assessment in August as Miss Sanderson spoke of goals she wanted to achieve when leaving custody.

She was discharged from the mental health team on December 17, three days before her death.

The teenager was initially due to be released on Christmas Eve but had four weeks added to her sentence for a separate matter.

Miss Sanderson told staff she was “not bothered” about the delay and said “it is what it is and I just have to get on with it”.

The inquest heard that Miss Sanderson became upset on December 21 following a row on the phone with her girlfriend.

But former inmate, Kerry Burgin said Miss Sanderson later asked her to practice a dance routine they were due to perform on Boxing Day.

She told the court Miss Sanderson was the “life and soul” of their dormitory” and that her death was a “complete shock”.

Noting the circumstances of her death, the jury stated: “It is worth noting that the coronavirus pandemic was prevalent during the entirety of Anneline’s time at HMP.

“This impacted a number of procedures and activities.

“There appears to be a lack of communication, accessibility and recording of records.”

Since Miss Sanderson’s death the mental health budget for HMP Styal had tripled to £1.5 million, Cheshire Coroner’s Court heard.

Greater Manchester Mental Health NHS Foundation Trust had also introduced a new key worker system which includes weekly welfare checks for more complex prisoners.

A senior psychologist now worked two a week at the prison while the waiting list for GP appointments had significantly reduced, the court was told.

Coroner Ms Davies said: “I am reassured since Annelise’s death that organisations have put in place new processes and tightened up those that were already in existence.

“This was a tragic loss of a young life, of someone who was determined to stay out of prison forever when she got out and was hopeful for the future.

“My sincere hope is that future prisoners will be better supported.”

Following the inquest, the family of Miss Sanderson, including her mother Angela Gray, said: “Her death has been incomprehensible and devastating, and we think it could have been prevented.

“Over the course of this week we have seen for ourselves how Annelise was treated in prison.

“She was just another number to them.

“Her mental health issues were seen as bad behaviour, and when she withdrew into herself she was just left to her own devices.

“She fell through the cracks despite asking for help from people who should have kept her safe.

“The past few days have been painful and enraging.

“We thank the jury for the attention they have given Annelise’s case and for recognising that there were failures in her care.”

Miss Sanderson was the youngest person to have died in a women’s prison in 20 years, the charity Inquest said, and one of 11 self-inflicted deaths at HMP Styal since 2007.

Inquest director Deborah Coles said: “Annelise had a history of trauma, and the mental ill health that often accompanies this.

“She deserved our understanding, care and support. Instead, she was viewed as a discipline and control problem by our public services. The fundamental question for all of us is why was she sent to prison in the first place?

“Deaths in Styal prison are at a record high and two self-inflicted deaths in December raise serious renewed questions about women’s health and safety.

“Each of these deaths is a stark reminder that prison is a disproportionate, inappropriate, and dangerous response to women in conflict with the law, not least for those with mental ill health.

“We need to dismantle prisons and redirect resources to holistic, gender-responsive community services. Only then can we end the deaths of women in prison.”

A Ministry of Justice spokesman said: “Our thoughts remain with Annelise Sanderson’s family and friends and we will carefully consider the inquest’s findings.

“We are investing up to £14 million to improve safety in women’s prisons and ensure the most vulnerable prisoners have access to round-the-clock care.”