A coroner has called for answers over the death of a forklift driver who went missing from a hospital before he was assessed by mental health experts.
Uyapo Hayunga-Macha was found in a Birkenhead dock in March, four months after his disappearance prompted a series of public appeals to trace him.
Senior coroner Andre Rebello has now questioned why the 28-year-old was not looked after once he attended Arrowe Park due to mental health concerns.
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The NHS trust that oversees the hospital told the ECHO it had held an internal investigation and was in the process of taking action, including providing additional staff training.
Mr Hayunga-Macha, known as Theo, was taken to Arrowe Park after an incident at his Birkenhead home on December 3, 2020.
He had telephoned his stepdad, telling him he had heard voices and feared people were trying to break into his flat.
Mr Hayunga-Macha locked the chain on his door before relatives persuaded him to let them inside, and it was shown there were no potential intruders.
He was taken to Arrowe Park in an ambulance but left of his own accord before experts had assessed his mental health.
His body was found in Morpeth Dock on March 9, just over four months after his disappearance.
An inquest into Mr Hayunga-Macha's death was held at Liverpool Coroner's Court last week, where a cause of death of drowning was given.
A narrative conclusion was issued, with the court hearing it remained unclear how he ended up in the water.
Mr Rebello, the senior coroner for Liverpool and Wirral, has now issued a Prevention of Future Deaths Report, also known as a Regulation 28 Notice, following the inquest.
Such a report gives a coroner the opportunity to raise concerns they believe may need to be addressed in order to prevent further tragedy.
In the report, a copy of which has been seen by the ECHO, he wrote: "On December 3, 2020 Merseyside Police were called to Theo where it was apparent that he was suffering from poor mental health.
"An ambulance was called and Theo agreed to be taken to Arrowe Park Hospital.
"It is reported that whilst waiting for triage that he left without being seen.
"Why was he not being looked after? And why was he left alone when waiting for assessment?"
Mr Rebello's report was sent to the North West Ambulance Service and the Cheshire and Wirral Partnership and Wirral University Teaching Hospital NHS trusts after he identified all three organisations as potentially having the power to prevent further deaths from occurring in similar circumstances.
The organisations each have until November 15 to respond.
A spokesperson for Wirral University Teaching Hospital, which oversees Arrowe Park Hospital, told the ECHO: "We would like to express our sincere condolences to the family and friends of Mr Hayunga-Macha, known as Theo.
"As a trust we accept the findings of the inquest.
"We have conducted a serious incident investigation and actions include strengthening our missing persons protocol, further staff training and improvements to the handover process with North West Ambulance Service.
"We are already taking action and will respond to the coroner with an action plan to make these improvements, along with partner agencies who were involved in this case."
A North West Ambulance Service spokesperson said: "We can confirm we have received the Regulation 28 notice from the coroner and are now reviewing matters in this case. We offer our condolences to Mr Hayunga-Macha’s family at this difficult time."
The Cheshire and Wirral Partnership NHS Foundation Trust was approached for comment.
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