The investigation gathered testimonies from a large group of former patients or their relatives who were in children's mental health units run by a single provider - The Huntercombe Group.

In response to our report, Dr Rosena Allin-Khan MP, Labour's shadow cabinet minister for mental health, has written to the Secretary of State for Health and Social Care Steve Barclay calling for a "rapid" review.

She said: "Yesterday's Sky News and Independent report into the treatment of young women at inpatient units run by The Huntercombe Group was extremely distressing.

"Patients, and their families, rightly expect to be safe in inpatient settings.

"With patients suffering from PTSD as a result of their treatment, the long-term impact of their experiences cannot be ignored."

Read more:
'Treated worse than animals': Investigation reveals decade of mistreatment in care of more than 20 teenagers

Sky News spoke to more than 20 former patients who went to Huntercombe units over a ten-year period - some as recently as February and March this year.

There were recurring themes in their complaints - from the overuse of restraint to inadequate staffing levels leaving people at risk of self harm.

Nikki Boughton-Smith is the mother of Amber Rehman - one of the patients we interviewed for our investigation.

She said: "I think a really important point is that these young people who have spoken out are not unique incidences.

"From the great work Sky News has done, we know others have been diagnosed with PTSD."

Asked about her daughter, Nikki said: "Amber is slowly finding the words to articulate her experience - which, like many of the girls have done - is very, very hard to do that."

In response to our report, mental health organisations said they welcomed a pledge by the Department of Health to investigate the issues raised by Sky News.

'Must never happen again'

Tom Quinn from eating disorder charity, Beat, told Sky News: "These reports of appalling practices and a failure to provide specialist treatment to help address patients' mental illnesses are shocking.

"We welcome news the Department of Health and Social Care are investigating these allegations. It's crucial this investigation is comprehensive and steps are taken to ensure this mistreatment is never allowed to happen again."

In a tweet, the Royal College of Psychiatrists said: 'It's devastating to hear the allegations of the awful treatment of 22 young women in a mental health hospital group over the last decade."

The Huntercombe Group merged with Active Care Group in December 2021.

It said: "The previous owners retain all the legal entities and associated records for these facilities prior to their acquisition. The current group is therefore unable to comment on the services provided prior to this date."

The previous owners, Elli Investments Group, said it regrets the hospitals, which were independently managed, failed to meet the expected standards for high quality care.

A Department of Health and Social care spokesperson told Sky News: "The allegations of mistreatment that have been raised are deeply concerning.

"We take these reports very seriously and are investigating the concerns raised and are working with NHS England and the CQC to ensure all mental health inpatient settings are providing the standard of care we expect."