Investigations have not found any sightings of Mr Vernon since he left his car in Sycamore Street in Wakefield.
Now, on the third anniversary of his last sighting, Humberside Police are issuing a renewed appeal for anyone who knows information about his disappearance to come forward.
Humberside Police scaled down the investigation in June 2015 after exhaustive investigations proved fruitless.
But he never reached Sheffield and the last sighting was of him walking down an alleyway on an estate in Wakefield. He was reported missing by his family the following day.
“There is no suggestion that criminal activity led to Damion going missing and we are keeping an open mind about his disappearance and the case will be kept open as a long term missing person enquiry.”