Archaeologists have uncovered a Stone Age "eco-home" which provides evidence of the earliest settlement discovered around Stonehenge.
But experts fear the highly significant find - and much as yet undiscovered archaeology - could be lost or damaged if the Government presses ahead with its plans to build a tunnel to remove the A303 from the World Heritage Site landscape.
The discovery has revealed a Mesolithic home, dating from between 4336BC to 4246BC, formed from the giant base of a large fallen tree used to make the wall of the house, with roofing likely to have been made from animal skins.
The earthy wooden wall has been lined with flints and the large pit created by the upturned roots lined with cobbles, while "exotic" stones brought from elsewhere were placed around the site as ornaments or mementos of other places.
David Jacques, archaeology project director at the University of Buckingham, said the residents would have been "sophisticated and clever," using stones from the hearth, which was also discovered, as primitive storage heaters to keep warm with at night.
Evidence has also been found of Auroch teeth, huge creatures even large than bulls, at the site at Blick Mead, which is close to a spring and around a mile from the later, Neolithic, monument at Stonehenge.
Mr Jaques said the find was "tremendously important" because it had previously been thought Mesolithic people were nomadic.
And it puts them in the important prehistoric landscape at the dawn of the Neolithic period, when Mesolithic people were thought to have been wiped out, and raises the question of whether they were the forefathers of those who built Stonehenge.
Mr Jacques, who has been running digs at Blick Mead for a decade, said: "This is a key site for where Britain began.
"It is the only continuously occupied Mesolithic site in Western Europe and we believe the eco-home is the sort of place the first Brits lived in."
But he fears that the 1.8 mile tunnel, announced last year by the Government to ease congestion on the A303 and remove the road from where it runs right past Stonehenge, causing noise pollution and breaking up the landscape, will damage the important archaeology in the area.
Efforts to preserve finds turned up by work on the tunnel, which will run within 20 metres of the current dig site, will be "rescue archaeology", with everything removed as quickly as possible and archived.
But discoveries which could be made with future developments in technology or because of in-situ circumstances such as environmental finds preserved in water-logged conditions will be lost, he argues.
He is urging the Government to consider making the Stonehenge area a national park and to reroute the road closer to Salisbury.
"We already know it's the longest used Mesolithic site in the whole of Europe and that the earliest monuments at Stonehenge were Mesolithic.
"How much else is there out there? These are the earliest British stories, covering the time from the point where it wasn't an island to becoming an island.
"They're our stories, and they shouldn't be being squandered."
Government heritage agency Historic England, the National Trust, which owns much of the land in the area, and English Heritage, which manages Stonehenge, said they all welcomed the announcement of the tunnel for the A303, which could bring environmental, cultural and economic benefits.
The organisations said they expected there to be full detailed environmental and heritage impact assessments, and that the importance of Blick Mead would be taken into account, as various options for the road scheme are developed.
Phil McMahon, inspector of ancient monuments for Historic England in the South West said: "There's no scheme available yet to understand the exact impacts of any road improvement proposal.
"But from our work on possible tunnel locations advising Department for Transport and Highways England over the past 18 months, we understand that any tunnel scheme is likely to be well away from the Blick Mead site.
"We will be keen to see that Highways England take full account of the Blick Mead site in developing and assessing a road improvement scheme, in addition to the very rich historic landscape of the Stonehenge World Heritage Site."
Ian Wilson, National Trust assistant director of operations for Dorset and Wiltshire said: "The landscape around Stonehenge is one of the richest in Europe and we would expect the importance of all archaeology to be taken into account."
He said the National Trust and Historic England were hosting a visit by World Heritage Site officials to familiarise them with the site and the Government's proposals for a new road tunnel this week, during which they would be highlighting the importance of Blick Mead.