Police said the man – who was found dead on 12 December on a hilltop next to the Dove Stone Reservoir on the edge of the Peak District, near Oldham – was trying to find the site of a 1949 plane crash at nearby Wimberry Stones, in which 24 people died.

There were only two male survivors and police are investigating whether he was one of them. Police have yet to release the man's name.

No friends or family have answered police appeals for information. Whether he intentionally travelled to the area to die or to kill himself remains unknown.

Police said there were "no apparent injuries or marks on the body" and they are not treating the death as suspicious.

Detective Sergeant John Coleman told the Manchester Evening News: "Why was the mystery man there? Had he spent a lot of his life in that area? Or has something exceptional happened in that area?

"We know there was a plane crash there in 1949 with 32 passengers and the majority died. Amongst the people that survived were two children – Michael Prestwich, who was 2, and 5-year-old Stephen Evans.

"Could he have been one of the children on the plane? Or could he be a relative of one of the flight crew or passengers? We have no evidence to support this yet but it's just another line of enquiry.

"In all my time as an officer I have never had an incident of this nature."

According to the Manchester Evening News, Michael Prestwich died aged 12 in a train accident, leaving police to figure out if the man is Stephen Evans.