Unesco has confirmed a warning that Stonehenge could be stripped of its world heritage site status, over its concern that a road tunnel, backed by the government, will irreversibly damage an area of “outstanding universal value”.
A report to Unesco’s world heritage committee setting out concerns about the £1.7bn A303 road tunnel was approved unchanged on Thursday.
Unless the designs for the two-mile (3.3km) tunnel are extended and changed, the committee recommends placing Stonehenge on Unesco’s list of world heritage in danger next year.
Last month the high court was told a decision by Grant Shapps, the transport secretary, to approve the tunnel last November was unlawful because it did not properly consider damage that would be done to a string of prehistoric sites and many thousands of ancient artefacts.
Unesco’s committee found that if the high court confirms planning consent for the tunnel, Stonehenge should be placed on its danger list.
It said that despite minor improvements to the original plan, the proposed cut-and-cover tunnel would irreversibly damage an area of “outstanding universal value”.
Shapps ignored advice from a Unesco mission in 2018 and his own Planning Inspectorate that the tunnel would cause “substantial harm” and should not go ahead. Unesco had recommend a longer, bored tunnel so more of the proposed dual carriageway would be covered.
The committee expressed dismay that Shapps chose the cheaper option of a short and shallow tunnel. It noted: “The state party [the UK government] determined that the additional landscape benefits would not justify the additional costs … It is regretted that for such an iconic world heritage property, the arguments persist that the perceived benefits of a longer tunnel do not outweigh the costs.”
It added: “The scheme should be modified to deliver the best available outcome for the OUV [outstanding universal value] of the property.”
The committee said a proposed 150m “green bridge” to west of the proposed tunnel “could not be considered an appropriate solution”. It notes that about 1km of the proposed new dual carriageway will be “exposed in a wide cutting within open landscape”.
The committee also appeared to rule out further talks with the UK government unless it commits to abandoning the current tunnel. It said: “While it is noted that the state party is committed to engage further, if the permission which has been granted were to be upheld by the high court, it is unclear what might be achieved by further engagement, as it would not be possible to compensate for the unacceptable adverse impacts of the present scheme.”
Last month the Department for Transport said: “We are confident the decision taken by the secretary of state to proceed with the A303 Stonehenge project was correct, lawful and well informed. The reasons are set out in the decision letter. We cannot comment further as this is a live litigation case.”
Stonehenge Alliance, which is campaigning against the tunnel, tweeted: “There is no act of ‘reverse vandalism’ if #StonehengeTunnel proceeds.” It called on the government to heed the views of Unesco and its own inspectors.