A teenager was allowed to walk out of a mental health unit and take her own life – hours after warning staff about her state of mind.

Alice Gibbs, from Barnet, died on October 14, 2013 after being hit by a train at Mill Hill Broadway Station.

The 17-year-old was receiving treatment at The Beacon Centre mental health unit in Edgware Community Hospital, and was meant to be on one-to-one observations at arm’s length – meaning she would not have been able to leave without permission.

However, her level was downgraded, and she was able to leave the unit.

At an inquest into her death at North London Coroner’s Court last month, Coroner Andrew Walker recorded a verdict that her death was contributed to by neglect.

The court heard that a note written by Alice, revealing her state of mind, had been passed to ward manager Daniel Keith hours before she was allowed to leave the unit – but this was not disclosed to a meeting of health workers.

Coroner Walker said: “There was a serious failure not to ensure that the MDT (multi-disciplinary team) meeting on the day of Miss Gibbs’ death knew of the concerns about a change in her mental health state.

“Had this change in her mental state been known it is likely that her observations would not have been changed from one-to-one observations which would have prevented her from leaving the unit. In this respect her death was contributed to by neglect.”

Mr Walker also said that the family had raised concerns about Alice’s state of mind.

During the inquest, Abigail Anorjin, charge nurse at the Beacon Centre, denied Alice’s father had warned her that she was intending to leave the unit to kill herself.

Mr Walker said he accepted entirely Mr Gibbs’ account of the conversation.

Before she was allowed to leave the unit, Alice repeatedly told care workers and her parents that she wanted to leave.

Lawyers at Irvin Mitchell, representing the family, said this meant she should have been closely monitored by staff.

Matthew Bebb, a specialist medical negligence lawyer at Irwin Mitchell, said: “Alice’s family have been left absolutely devastated by her death. This is a very difficult time for them and while the inquest has gone some way in providing answers to the many questions they had, they remain concerned about the care she received before she died and want reassurance that improvements will be made.

“I would like to thank the coroner for conducting a very thorough investigation into the circumstances surrounding of Alice’s death and concluding that her death was contributed to by neglect.

“It is now vital that lessons are learned to ensure that vulnerable young people are provided with the appropriate level of care and observation and in the correct environment for their needs, in order to prevent these types of tragedies occurring in the future.”

Her mother said: “The impact of Alice’s death on our family has been enormous; we have struggled to come to terms with what has happened.

“I have developed a general mistrust of the mental health services as a result of Alice’s death and the way she was severely let down by the medical professionals that we entrusted to care for her.

“Alice was a child in crisis and I feel that there was a year of wasted opportunities in the mental health service, followed by the final failures at the Beacon Centre to care for her and keep her safe.”

In a statement, the Barnet, Enfield and Haringey Mental Health NHS Trust, which runs the unit, said: “We offer our sincere condolences to the family and we deeply regret the death of a young woman in our care whom we accept, did not receive the high level of care and support we strive to provide for all of our patients and those who use our services.

“In 2013, immediately after the death was reported to the trust, the director of nursing commissioned a full, thorough, external and independent investigation.

“The investigation led to a series of recommended actions and a comprehensive action plan which included appropriate training and support for all relevant members of staff.

“The action plan was acknowledged by the coroner, who found no evidence of systemic failures on the part of the trust, as being robust and effective. It was delivered in full, immediately after its completion in 2013/4.”