David Jacques with members of the dig at Blick Mead

Archaeologists from the University of Buckingham have discovered a Mesolithic encampment near the ancient monument.

The discovery could reveal for the first time how Britain’s oldest ancestors lived – but the precious site could be damaged if plans for a tunnel at Stonehenge go ahead.

A 1.8-mile tunnel is part of a £2 billion plan announced by Prime Minister David Cameron to make the nearby A303 a dual carriageway.

David Jacques with members of the dig team at Blick Mead

Charcoal dug up from the encampment at Blick Mead, a mile and a half from Stonehenge, has now been scientifically tested, revealing that it dates from around 4,000BC.

The dig has also unearthed evidence of possible structures in the only untouched Mesolithic landscape in the Stonehenge World Heritage Site.

There is also evidence of feasting, including burnt flints and remains of giant bulls, called aurochs, eaten by early hunter gatherers, as well as tools.

University of Buckingham research fellow David Jacques made the discovery on a dig which launched the uni’s Archaeology MA course in October.

Mr Jacques said: “British pre-history may have to be rewritten. This is the latest-dated Mesolithic encampment ever found in the UK.

“Blick Mead could explain what archaeologists have been searching for for centuries – an answer to the story of Stonehenge’s past.

“But our only chance to find out about the earliest chapter of Britain’s history could be wrecked if the tunnel goes ahead.”

Mr Jacques added: “The PM is interested in re-election in 140 days. We are interested in discovering how our ancestors lived 6,000 years ago.”

The discovery at Blick Mead connects the early hunter gatherer groups returning to Britain after the Ice Age to the Stonehenge area all the way through to the Neolithic in the late 5th millennium BC, said Mr Jacques.

He said: “Britain is beginning across this time period. Blick Mead connects a time when the country was still joined to the mainland to it becoming the British Isles for the first time.

“Was Stonehenge built in part as a monument to the ancestors from the deepest part of Britain’s past?”

Prof Tim Darvill, of Bournemouth University, said: “This is the most important discovery at Stonehenge in over 60 years.”

Andy Rhind-Tutt, chairman of the Amesbury Museum and Heritage Trust, said: “Traffic congestion to one of the country’s most visited attractions will not be solved by a tunnel with one exit lane. The current tailback can extend five miles and can take two hours to get through.

“Any tunnel would need to be motorway standard, and even with four lanes there would still be tailbacks.

“Concerns have been raised about the water table. Due to the chalkland landscape the tunnel would effectively become a dam, which would change the water course, causing problems. Kilometres of chalk would have to be extracted. Air conditioning, water pumps, lighting and maintenance costs would be colossal. A much more practical solution would be to reroute the A303, supporting South Wiltshire as well as the West Country.”

More than 1,000 people have already signed up for a new Stonehenge MOOC (online study course) launched today, Friday, by the University of Buckingham.