UK government approves Stonehenge tunnel plans

Transport secretary Mark Harper has granted a Development Consent Order for the A303 Stonehenge scheme, which comprises 12.9km of new dual carriageway, including a 3.2km tunnel.

National Highways’ proposals were initially granted consent in 2020 but, following a legal challenge over concerns about the environmental impact on the Unesco World Heritage site, the decision was overturned by the High Court a year later. 

The scheme aims to relieve the notorious congestion on the single carriageway section of the A303 as it passes the ancient stones, and improve journey times and reliability between the M3 and M5 motorways.

National Highways chief executive Nick Harris described the A303 Stonehenge scheme as “part of the biggest investment in our road network for a generation”.

“The [government’s] decision follows a lot of work on a comprehensive year-long process to reassess our Development Consent Order, looking in detail at possible alternatives, also including cumulative carbon and heritage issues.

“It means we’re now a step closer to solving the long-standing issues of congestion and delays on the existing A303, improving journeys for all our customers and bringing much-needed relief to local communities.

“The investment, along with other improvements along the A303, will help to boost the south-west economy, improve journey reliability, remove the sight and sound of traffic from this very busy road and return one of our most important World Heritage Sites to something like its original setting.”

The A303 Stonehenge upgrade includes: 12.8km of dual carriageway between Amesbury and Berwick Down; a tunnel at least 3.2km long underneath the World Heritage Site, closely following the existing A303 route, but a further 50m away from the Stonehenge monument, avoiding important archaeological sites and intrusion on the view of the setting sun from the stones during the winter solstice; a new bypass to the north of Winterbourne Stoke; and junctions with the A345 and A360 either side of the World Heritage Site.

Derek Parody, National Highways’ project director for the scheme, said the project aimed to conserve and enhance the World Heritage site and this was being achieved through collaboration with heritage groups, including English Heritage, National Trust, Historic England and the independent A303 Scientific Committee.

“The scheme will not only sustain the Outstanding Universal Value of the Stonehenge landscape, it will also have a beneficial effect, and extensive archaeological studies and assessments have been undertaken to provide evidence of the benefits that the scheme will deliver for the World Heritage Site,” Parody said.

“The decision represents a major milestone, not only for us as the project team, but for all those who have supported this project over a number of years; our stakeholders, the heritage bodies, local and regional businesses and indeed local communities.”

National Highways is now analysing the detailed changes in the Development Consent Order and assessing timescales. It anticipates starting preparatory work next year.

There is now a six-week period in which parties can lodge an intention to legally challenge the decision, and in the meantime, National Highways will renew its plans to prepare for the scheme.

Last year the company awarded the main works contract to the More joint venture, comprising FCC Construcción, WeBuild and BeMo Tunnelling, to deliver the £1.25bn (US$1.64bn) tunnel and main construction work.

Costain and Mott MacDonald will be the company’s delivery assurance partner, providing technical and construction management expertise by helping to mobilise the main works contractor, oversee construction, assist the discharge of consent requirements and assure the design.

The construction phase is scheduled to take five years to complete and ahead of the main work, Wessex Archaeology will carry out archaeological mitigation work, while Octavius (formerly Osborne Ltd) will undertake preliminary work, including the reconfiguration of local authority roads.

Archaeological fieldwork and preliminary work will be carried out before the start of the main construction phase.