Simon Parfitt, of the Institute of Archaeology at University College London, told a press conference at the British Association's meeting in Loughborough that 'Boxgrove Man' - who lived about half a million years ago - ate meat, raw or rotten, from horses, rhinos, red deer and cave bears.
The evidence for his existence is a solitary tibia, or shin bone, unearthed at Boxgrove near Chichester in West Sussex last year.
The bone was put through a computer-enhanced X-ray scanner at University College Hospital and was found to be 'massive compared to that of a modern human', Mr Parfitt said. 'The bone is incredibly thick, with extremely developed muscle ridges.'
The man would have stood about six feet tall, with muscles like Mike Tyson. Archaeologists believe that the bone belonged to a man because of his size and height. He was active and did a lot of running, Mr Parfitt added.
He said the surface of the bone was well-preserved with grooves and circular marks which indicated that 'the tibia has been chewed by a carnivore - possibly a wolf'.
Researchers are now examining slivers of the shin bone to see if Boxgrove Man ate fish as well as meat.
Archaeologists have been studying Boxgrove for more than a decade and 'there is no other site in Europe which is producing so much detail' about the way of life and the diet of the continent's earliest inhabitants, according to Mr Parfitt. The gravel pit site was an early factory for flint hand- axes and was intensively occupied for more than 5,000 years. But, until last year, no human bones had been found.
Archaeologists have also discovered at the site the almost complete skeleton of a horse which had been dismembered. They hope that it will settle 'one of the biggest debates in Stone-Age archaeology', Mr Parfitt said - whether the earliest humans were scavengers or hunters.
The bones of the horse carry the marks of stone-cutting tools lying under the marks of carnivores' teeth.
This would suggest, he said, that either the humans got to the horse carcass before any carnivores, or that they drove the carnivores away from the kill, or that the humans themselves hunted and brought down the horse. To settle the argument, the researchers are now looking for the possibility of damage from a spear.
Mr Parfitt believes that Boxgrove Man is an example of Homo heidelbergensis, an ancestor of Neanderthal Man who survived in Europe until the emergence of early modern humans about 30,000 years ago.
Modern humans evolved in Africa, probably as descendants of Boxgrove Man's African counterparts, so Homo heidelbergensis is an ancestor of both groups.Reuse content