The agency said it was committed to protecting historic landscapes

The agency said although work has started to ease the bottleneck on the A30 at Goss Moor, it is to survey aspects of an ancient settlement.

The site includes a rare 'fossilised' landscape, with walls, banks and hedges untouched since medieval times.

A spokeswoman said time and resources would be given to investigate any historic features which are discovered.

Cultural heritage

Ginny Clarke said: "The quality and rarity of these finds illustrate the importance of the care taken while developing and preparing for major road scheme.

"We're working to improve our assessment of the impact of our work on the landscape. We are also looking to enhance our work to predict the location of possible remains so we can determine the best approach to be taken."

The Highways Agency is supporting the Council for British Archaeology's week as part of its commitment to protect the country's cultural heritage.

It said as builder and operator of England's motorways and major A-road network, it is committed to minimising the impact of its projects on historic landscapes.

The new road in Cornwall, which is expected to take two years to complete, will skirt the northern edge of Goss Moor, connecting two dualled sections between Bodmin and Indian Queens.

It should ease congestion around the Iron Bridge, a notorious traffic and accident blackspot.

But the �69m scheme has been criticised by some environmentalists who claim it could wipe out rare species of flora and fauna.