MYSTERY still surrounds the circumstances in which a Blackpool man ended up with a life-threatening head injury, detectives have admitted.

Jonathan George Key, 42, of Withnell Road, Blackpool, was found unconscious on Middle Walk off Blackpool Promenade by a dog walker early on Thursday morning (April 24).

He had an injury to the back of his head and was taken to Blackpool Victoria Hospital where he was also found to have suffered a brain haemorrhage.

He was then transferred to Royal Preston Hospital where his condition was described as 'critical'.

Officers working on the case still don't know whether Mr Key was attacked, or whether he fell before, or as a result of, developing a brain haemorrhage.

And how Mr Key -- known as 'walkabout Jon' by friends because of his tendency to go off alone -- came to be on Middle Walk is unknown.

Detectives have been scouring town centre CCTV footage in a bid to piece together the hours leading up to his discovery on Thursday morning.

He was last seen at the Hop Inn off King Street, Blackpool at closing time on Wednesday (April 23).

"We have got this time gap between 11pm and 6.15am of where he's gone," explained detective inspector Pat Gill.

"We are looking at CCTV and we are appealing to anybody that knows Jon, his movements after he left the Hop Inn, or anybody that was in the Middle Walk area in the early hours who might have seen anything, to come forward."

In particular police are keen to trace two fishermen and a man with short, blond, spiky hair, all said to have been in the Middle Walk area at the time Mr Key was found.

DI Gill urged anyone with information to contact the police on 293933.