The Police Ombudsman has recommended that two part-time police officers be disciplined after failing to take appropriate care of a man who was found lying on the ground in Belfast City Centre in May 2009.
Al Hutchinson also found that civilian CCTV operators employed by the PSNI failed to summon any assistance for the 44-year-old, who was shown on footage to be unresponsive over a period of several hours.
The man, who appeared to have been drinking heavily, was later also found to have suffered a fractured skull and bleeding in the brain, which has affected his memory and communication skills.
"It is a matter of serious concern that two police officers and police CCTV operators failed in their duty to protect the welfare of a man who was clearly in a vulnerable condition in Belfast city centre," he said.
"Thankfully, the man's injuries were later identified by other police officers whose prompt action in securing medical assistance may have saved the man's life.
"I have made a series of recommendations which I hope will ensure this situation does not occur again, and I am encouraged by the police response to these."
Police were first summoned to the man's assistance at 3pm on 12 May 2009. A member of the public reported that the man had been assaulted and was lying on the ground close to Belfast's Dublin Road.
Two officers attended and noted that the man seemed drunk. The officers took appropriate action, summoning medical assistance and checking with him whether he had been assaulted. He said he had fallen and suffered a slight bump to the head. After being seen by paramedics, he refused to attend hospital.
Shortly after 8pm that evening two other officers found the man lying on the ground not far from where he had originally been seen. CCTV footage showed that the officers stayed with the man for about ten minutes, before walking off leaving him lying on the ground. No medical assistance was requested by the officers.
Just under an hour later a member of the public, who had noticed that the man had been lying on the ground without moving for two hours, used a nearby emergency telephone to contact police. Paramedics were summoned to the scene and took the man to hospital.
He was escorted from the hospital by security staff at around midday the following day after causing a disturbance, but was readmitted just over an hour later after reportedly collapsing a short distance away.
He was involved in a further disturbance in the hospital before being once again removed from the premises at around 2.20pm.
Police Ombudsman investigators viewed CCTV footage of both occasions on which he was escorted from the hospital, but despite door-to-door enquiries with businesses and local households, were unable to determine his whereabouts between then and his arrest at 18:45hours that evening.
It was only when he had been placed in custody following his arrest that police discovered the serious head injury and immediately requested an ambulance to take him to hospital.
While praising the custody officers who sought immediate medical attention, which may have saved the man's life, Mr Hutchinson said it was unacceptable that two officers had earlier left him lying on the ground without seeking medical attention. Neither had they recorded the incident, as required, in their police notebooks.
Police Ombudsman investigators also discovered that the guidance and training given to CCTV operators focused on the detection and prevention of crime, but made no specific reference to protecting the welfare of members of the public.
"The role of CCTV operator as outlined by the police is too narrow, and must be reviewed to ensure they also have a duty to protect life," said Mr Hutchinson, who also recommended that police should investigate the actions of the civilian operators involved in the incident.
In addition, he recommended that the PSNI should ensure that all police officers, whether full or part-time, should be trained in first aid and their duty to protect life, before being allowed to commence duties.