Plans to build a tunnel past Stonehenge risk destroying a nationally important nearby Ice Age site an archaeologist has warned, as he accused the Government of wrongly marking its location on a map.

The Blick Mead site a mile-and-a-half from Stonehenge can trace a human presence back to the last Ice Age, but is under threat from a £1.6bn scheme to improve the road past the world’s most famous stone circle.

Prof David Jacques of the University of Buckingham said the planned tunnel on the A303 in Wiltshire and a flyover could irrevocably damage the site which provides insight into Britons’ shift from hunters to farmers.

Prof Jacques said the impact on the site had not been assessed, despite it being the only place in Britain that can trace people living there since the end of the Ice Age, around 8,000 BC.

Building a tunnel and flyover risks lowering the water table, and drying out the peat and silt conditions which preserve archaeological remains, he said. Roadworks in the 1960s have already dramatically thinned the protective peat covering.