The Priory is facing a fine of millions of pounds for breaching health and safety laws after a 14-year-old girl with a history of suicide attempts hanged herself in its care.
Amy El-Keria was found in her room at Ticehurst House in East Sussex in November 2012 while receiving treatment at the Priory, which runs mental health services as part of a contract with the NHS.
A criminal investigation was launched by the Health and Safety Executive into the private mental healthcare group after her death.
On Wednesday afternoon the London-based company indicated a guilty plea after being charged under health and safety laws with being an employer failing to discharge its duty to ensure people were not exposed to risk.
The packed courtroom heard the company would be admitting the offence formally at a Crown Court sentencing hearing next month in front of a judge with the power to impose an unlimited fine.
The company has a turnover of £134 million for the year ending 2016 and the starting point for the fine would be £2.4 million, Sarah Le Fevre, prosecuting, said.
The teenager was an NHS-funded patient in The Priory’s care at the East Sussex hospital’s children’s unit near Tunbridge Wells.
On August 23 2012, she was admitted to the hospital’s high dependency unit and on November 11 that year she tied a scarf around her neck in her bedroom, the court heard.
She was found at 8.15pm and taken to hospital by 11pm but died the following day after life support was withdrawn.
Ms Le Fevre told the court she had a “known and recent history of ligature attempts (which) continued during her time there”.
But she was left with unsupervised access and the means to carry out another suicide attempt, the court heard.
The Health and Safety Executive investigation concluded “procedures for the management of ligature risk had not resulted in effective measures”, Ms Le Fevre said.
An inquest in 2016 heard neglect contributed to her death, finding she died accidentally of unintended consequences of a deliberate act.
The case finally went ahead after a series of delays and court administration errors.
District Judge Tessa Szagun apologised to Amy’s mother Tania for the problems this had caused.
Speaking after the hearing, Ms El-Keria said she wanted to see more transparency in the private healthcare sector.
She said: "You have the 'what ifs' always. And she was just a child. And a vulnerable child.
"And that's what I want to say to people. They don't realise what's happening to our children in these places.
"We need change. We need to be more open, more transparent in these private hospitals. We thought we were doing the best for her."
"We put her in there. We didn't want any of this to happen, obviously.And the first coroner said they didn't want to put a reputable institution into disrepute. Nor did I. I wanted her home with me."
The company is expected to be sentenced at Lewes Crown Court on February 6.
The Priory Group said in a statement: “We are truly sorry that this very sad incident occurred and extend our deepest sympathies to Amy’s family.
“We continue to invest significantly in improving patient safety at Ticehurst. The hospital is making strong progress under new leadership and continues to be rated ‘good’ in all areas by the CQC.”