A lengthy investigation, lasting nearly two years, has failed to uncover an explanation for how a mystery man was found dead next to Mitcham Common.

The skeleton of a man, who has still not been identified, was discovered near an industrial site in Red House Road, on the border of Croydon and Merton boroughs, on January 17, 2011.

He was discovered by Mark Burrows and Keith Conway, who were searching the area for scrap metal, Westminster Coroner’s court heard today.

Detective Inspector Chris Stanley, from the Metropolitan police’s serious crime operations department, told the court the unknown man was found underneath a pile of rubbish and that the area was notorious for flytipping by builders.

Det Insp Stanley said: “That is significant because the body could have come from the back of a lorry, or the person died of natural causes and people dumped material on top of him.”

He added: “They [Mr Burrows and Mr Conway] were in quite a state of shock. The leg was quite distinctive and that was what brought suspicion to their minds.”

Police followed a number of lines of inquiry, including whether the dead man was a vagrant from eastern Europe, if he had died sleeping in the Common, or whether he had been dumped there after dying elsewhere.

Dr Robert Chapman, a pathologist who examined the body at St George’s Hospital, was unable to say how the man died.

There were no neck injuries to suggest he had been strangled, no blood found on his clothing, and no head injuries, nor were they any breaks to his bones.

But Det Insp Stanley said murder could not be ruled out as the pathologist was unable to test the man’s internal organs for stab wounds, or signs of poisoning, because the body was almost completely decomposed.

But another expert pathologist, Dr Freddy Martin, was able to estimate the man had died on between September 29 and October 3, 2010 – which coincided with a complaint to police by a dog walker who had reported a foul smell in the area at that time.

The man was estimated to be between 5ft 5in and 5ft 7in, white ethnicity with dark brown straight hair, had poor dental hygiene and was between 50 and 55-years-old.

Further tests revealed his clothes had been in manufactured in Hungary by a business which since has gone bust.

Despite a search of the UK’s DNA database, and similar databases across Europe, police were unable to establish any match.

This was significant because, Det Insp Stanley explained, a vagrant’s DNA would be expected to be on the database because “they would have had some contact with the police and it is standard procedure for a DNA sample to be obtained and stored.”

The Met Police even called for help “at significant cost” from scientists at the University of Dundee, who, using insects to clean the skull, they were able to use a computer to reconstruct what the face would have looked like (pictured) with 70 per cent accuracy.

A public appeal for information yielded information from two ladies who said they saw a vagrant matching the man’s description walking around the area with several eastern Europeans.

This led police to suspect the man may have travelled to Mitcham Common in the back of a lorry and stayed around the area because it was close to Lunar House, an immigration office in Croydon.

The coroner, Dr Shirley Radcliffe, recorded an open verdict and closed the inquest, but hoped the man’s identity would be discovered one day.

She said: “Nearly two years later, the police have undertaken a remarkable investigation that has covered every possible aspect they can to identify the individual to find out how he died.”