The scene in Great Victoria Street where area is cordoned by police at Grand Opera House

THE Police Ombudsman has launched an investigation after a man arrested by police following a “violent” incident in Belfast is now critically ill.

The Ombudsman’s office has said it is believed CS spray was used during the incident on Great Victoria Street in the early hours of Thursday.

One theory is the victim – who was seen in the area in his underwear – may have sustained a head injury during the incident.

Part of the city centre has been cordoned off by police.

Officers said they were called to Great Victoria Street shortly before 5 am after a report that a man had become violent.

Witnesses said the man was dressed only in his underwear and had been behaving erratically.

Paul Murphy, senior investigating officer with the Police Ombudsman’s Office, said they were contacted about the incident by police at about 6.20 am.

“That incident related to a male who had apparently had an altercation with a number of taxi drivers,” he said.

“Police had responded and arrested that male.

“At some point during the arrest it appeared that CS spray was used.

“The male in question, his condition had deteriorated, he was then subsequently taken to hospital where his condition is now described as critical.”

He said “restraints” had also been used by police during the arrest.

Mr Murphy said a number of witnesses had come forward and some CCTV footage had been collected.

However, he appealed for anyone else who may have been at the scene to contact the ombudsman’s office.

“This is now a Police Ombudsman investigation, so the Police Ombudman’s Office will now take primacy and we’ll conduct an independent investigation into the circumstances surrounding the arrest and also the condition of the male in question,” he added.

A defibrillator was left at the scene beside the Grand Opera House.