Emergency services were called to The Guild in Fylde Road following reports a man's body had been found at around 7.20am yesterday (February 9).
His death was not being treated as suspicious and a file will be passed onto HM Coroner in due course, police said.
Officers said they were working to identify the man so his next of kin could be informed, but their "enquiries have proved unsuccessful" so far.
Det Sgt Lisa Hough, of Preston CID, said: "This man has died in very sad circumstances.
"Despite our best efforts we have been unable to identify him at this time or inform his next of kin.
"That is why we are now asking for the public's help."
The man is described as white, 5ft 11in tall, approximately 40 to 50-years-old, of slim to average build with a slim face, very short balding black/grey hair, a receding hairline, bushy grey and black eyebrows and a shaven beard with slight stubble to the chin.
He has a tattoo on his right forearm of a devil/demon with wings and on his left forearm is a tattoo of a skull with a black ponytail, black goatee beard, and purple detailing.
Officers said he also has scarring to his right shoulder, left knee and left ankle, which may be the result of surgery.
"If you know who this man is or who his friends or associates were then I would ask that you please get in contact with police," Det Sgt Lisa Hough added.
Anyone with information can contact police by calling 101 or emailing [email protected], quoting log number 0231 of February 9.
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