Police are appealing for help tracing Ian Jonathan Leaf, who was reported missing this afternoon (TUE).
Officers say his disappearance is out of character and they are becoming increasingly concerned for his welfare.
Police searches are underway and officers are also speaking with all those who know Mr Leaf or have had contact with him over recent days.
He is described as being 6ft 1inch tall, thin build, cleanly shaven and a lot of dark brown short hair with a parting to the left.
He has a pale complexion and brown eyes and is believed he may be wearing a black padded waterproof jacket.
Detective Chief Inspector Scott Hall said: "We're becoming increasingly concerned for Mr Leaf's welfare as going missing is out of character for him. "I'd urge anyone who sees him or knows of his whereabouts, or Mr Leaf himself, to make contact with us as soon as possible."
Anyone with information is asked to contact Northumbria Police on 101 ext 69191, quoting reference 452 07/01/14.