THE Government has been urged to rethink its plan for a road tunnel near Stonehenge.
UN cultural agency Unesco said it would have “adverse impacts” on the prehistoric monument.
And it warned the site was at risk of being placed on the list of world heritage in danger if changes are not made.
Transport Secretary Mark Harper approved the £1.7billion scheme in July, which will see a two-mile tunnel built on the A303.
Campaigners from The Stonehenge Alliance and Save Stonehenge World Heritage Site sent a petition to Unesco HQ in Paris earlier this month.
The petition, bearing 225,000 signatures from 147 countries, demanded the Government halt plans for the “damaging” road revamp in Wiltshire.
Yesterday a report from Unesco responding to the calls, said the scheme “should not proceed in its current form”.
It said the planned western portal and associated dual carriageway “would have significant and inappropriate adverse impacts on the physical and visual integrity” of Stonehenge — which is in a congestion hotspot.
David Bullock, National Highways’ Project Manager for the scheme, said: “We remain confident this is the best solution for tackling a long-standing traffic bottleneck in the South-West.”