What is the Stonehenge tunnel project and why is it so controversial?

Government wants to build a two-mile tunnel near Stonehenge - but campaigners say it will destroy the site’s unique landscape

A three-day legal fight over the future of Stonehenge kicks off at the High Court this week as campaigners try to block a tunnel project near the iconic monument.

A group of archaeologists, environmentalists, historians, transport experts, countryside campaigners and druids will try to stop the building of a highly controversial road tunnel along the A303 in Wiltshire - a major route between the southeast and southwest - for the second time.

Save Stonehenge World Heritage Site (SSWHS) and the Stonehenge Alliance (SA) are challenging the government’s decision to approve the project, which they claim could put the prehistoric site’s Unesco world heritage status at risk.

The campaigners have had to crowdfund for their legal fees with John Adams, SA chair, describing the court showdown as a David and Goliath battle.

What are the plans for the tunnel?

Government wants to build a two-mile long tunnel near Stonehenge (Highways England)

Highways England (HE) says it wants to transform the A303 at Stonehenge, a bottleneck that is notorious for drivers due to long tailbacks.

The road agency says that at peak times the eight-mile journey between Amesbury and Berwick Down - along the single-carriageway A303 - can take over an hour.

HE wants to replace the single-carriageway road, used by thousands of people daily, with a dual-carriageway between Berwick Down and Amesbury, two-miles of which will come in the form of an underground tunnel at Stonehenge, one of the world’s most famous monuments, which dates back to the late Neolithic Age and attracts more than a million visitors annually.

Computer generated image of what the tunnel could look like (Highways England)

The government agency says that the dual-carriageway will create extra capacity on the road and reduce traffic at Stonehenge. HE claims this will reduce journey times past Stonehenge from 1 hour at peak times to just eight minutes, “helping businesses and people get from A to B, creating jobs and boosting the local economy”.

The proposals, backed by Wiltshire Council, would mean the A303 is removed from sight near Stonehenge. At present the road goes directly past the world-famous tourist attraction.

What are the objections?

SSWHS and SA claim that the project will greatly harm the area around Stonehenge, describing the plans for the tunnel as an act of “vandalism”.

Mr Adams argues the Stonehenge site is crucial to protect not just for the benefit of the UK, but the whole world and claims the plans reduce journey times by “only a few minutes” and are a poor use of public funds.

In 2019, before soaring inflation hit the UK, the government put the project’s price at £1.7bn - SA claims it will end up costing closer to £2.5bn.

The Stonehenge site was declared by Unesco to be a World Heritage Site of Outstanding Universal Value in 1986 (Steve Parsons/PA) (PA Archive)

Map of proposed project (Highways England)

Campaigners argue that Stonehenge is more than a monument and that the landscape around the site is packed with millions of archaeological artifacts and other remains. They argue the construction necessary to build the tunnel would destroy a landscape “that holds many secrets yet to be discovered”.

In 2020 a circle of deep shafts was discovered near the Stonehenge site, which archaeologists described as the largest prehistoric structure ever found in Britain.

Rowan Smith, a solicitor for Leigh Day acting for the campaigners, said the government ignored calls for a fresh public examination of the plans and that ministers gave “no regard whatsoever” to the possibility that the plans could put Stonehenge’s world heritage site at risk.

Stretch of road near Stonehenge is renowned for traffic jams (PA Archive)

“Despite this road development being so controversial, and despite important new matters which required proper scrutiny, the secretary of state ignored calls for a fresh public examination,” he said.

“Our clients consider that was unfair and potentially a breach of human rights. Also, no regard whatsoever was given to the risk that Stonehenge would lose its world heritage status if plans were approved, which our clients say was plainly irrational. We look forward to presenting these arguments to the court.”

So far, more than 230,000 people have signed a petition against the proposals and Unesco, which awarded Stonehenge world heritage site status, said the plan should not go ahead without “amendments”.

Unesco said in a report last year that surface roads should be considered to protect land around the site.

What are the arguments in favour?

The planned work at Stonehenge is part of a wider programme of A303/A358 corridor improvements announced as part of the road investment strategy 2015-2020.

The government said the schemes were aimed at enabling “growth in jobs and housing by providing a free-flowing and reliable connection between the southeast and southwest.”

Ministers, local businesses and councils argued that slow journey times along the A303/A358 were a barrier to economic growth in the region.

The National Audit Office said in a 2019 report that any potential benefits from building the tunnel would only be realised as “part of a completed A303/A358 corridor” redevelopment.

Campaigners say road will end up costing £2.5bn (PA)

“On its own, the Amesbury to Berwick Down project delivers some localised transport and economic benefits such as reduced congestion in the local area,” the report said.

“It will also improve the setting of the Stonehenge monument by removing much of the road from the World Heritage Site.

“However, the project can only create a high-quality route to the southwest and unlock the full growth potential in the region in combination with the seven other projects identified by Highways England as necessary to upgrade the A303/ A358.”

So far only three of these have been funded, campaigners said.

Is this the first legal challenge to the plan?

Transport secretary Mark Harper greenlighted the project again this year (PA Wire)

No. The government first green-lighted the plans in 2020 but they were quashed following a successful campaign at the High Court in the following year. In his ruling, Mr Justice Holgate said the government’s decision to allow the project to go ahead was “unlawful” on two grounds.

He said there was a “material error of law” in the government’s decision-making process as there was no evidence of the impact on each asset at the site.

But the Department for Transport approved it again in July this year, sparking the second legal challenge by campaigners.

Mark Harper, the transport secretary, said in a 64-page letter he was “satisfied there is a clear need" for the new tunnel and the project’s “harm on spatial, visual relations and settings is less than substantial and should be weighed against the public benefits”.

The letter said there was a “number of benefits that weigh significantly in favour of development”.

Mr Harper added that, in “respect of cultural heritage and the historic environment”, he recognised “he must give great weight to the conservation” of the World Unesco Heritage Site and accepts “there will be harm as a result of the development to cultural heritage and the historic environment”.