Detective Chief Inspector Richard Ocone said the body was "pretty decomposed, and was in effect a skeleton" when it was found near the A419 at Cirencester, a town built on the ruins of an ancient Roman town.
Gloucestershire Police said there was no reason to believe there were any suspicious circumstances behind the man's death but they hired experts from Liverpool John Moores University to reconstruct his face in the hope his relatives or friends may recognise him.
The man was aged somewhere between 30 and 55, was around five feet seven inches tall and is thought to have been white and probably a British national.
We are appealing for information to identify a man, whose remains were found on the edge of the Bathurst Estate in Cirencester. The discovery was made close to the A419 in between Stroud and Cirencester on Tuesday 1st May 2018. For more information please watch the below: pic.twitter.com/FQlVcKDGaC— Glos Police (@Glos_Police) 10 April 2019
At the time of his death the man was wearing a Peter Storm raincoat, a grey/blue short-sleeved shirt, a black gilet and blue trousers with a dark leather belt.
A beige baseball cap and dark trainers with a white sole were found nearby, adding to the mystery.
"We're potentially dealing with somebody who's perhaps walking distances between locations, and having no ID or money or a wallet on them is part of their lifestyle," said DCI Ocone.
"It's a bit of a quandary at the moment, we just need to know who he is. This man will be somebody's son; he may well be somebody's brother or uncle," he said.
The police have been unable to find a match on the DNA database — suggesting he had no criminal convictions — or on the missing persons.
It is not the first time facial reconstruction experts have been used to identify a body.
In January 2000 a body was dumped in a large sports bag on a quiet industrial estate in Attercliffe, Sheffield.
South Yorkshire Police hired a facial reconstruction expert and the body was eventually identified as Mohammed Nasser Ali, 75, a retired steel worker.
Despite all of the necessary forensic and DNA examinations taking place we’ve been unable to identify this individual. However several distinctive items were found near to the body which may help to identify him. For more details please watch part two of our appeal video below: pic.twitter.com/k8vFb3THCP— Glos Police (@Glos_Police) 10 April 2019
In March 2001 two men — one of them a Yemeni asylum seeker — were jailed for life at Sheffield Crown Court for Mr Nasser Ali's murder.
In 2004 a body was found in the Yorkshire Dales. An artist's impression was eventually produced and last month the body was identified as that of Lamduan Seekanya, a Thai woman who moved to the UK after marrying British teacher David Armitage.
"I didn't kill my wife. Absolutely not," Mr Armitage told a journalist from The Sun newspaper, which tracked him down to his home in Thailand last month.