In its 2020 national budget, the UK Government allocated funds for construction of the long-awaited A303 Amesbury to Berwick Down road upgrade scheme passing the ancient Stonehenge monument in south England. In his speech, Chancellor of the Exchequer Rishi Sunak announced a £27 billion investment in road improvements over the next five years and singled out the £1.7 billion A303 scheme.

The upgrade includes a 3.3km twin-tube tunnel to relocate the current surface road underground as it passes the Stonehenge World Heritage Site.

Funding agreed for proposed A303 road link

Following submissions at the end of 2019 to undertake the planned design-build of the project, Highways England, the project owner responsible for major roads and motorways in the country, selected three international joint ventures for the next stage of the procurement process:

• BMJV of Bouygues Travaux Publics and J Murphy & Sons;
• HDJV of Hochtief Infrastructure and Dragados;
• MORE JV of FCC Construcción, Salini Impregilo and BeMo Tunnelling UK.

From April 2020, the three JVs will be invited to participate in a dialogue with Highways England over a six-month period before submitting their final tenders. The preferred bidder is expected to be announced in 2021.

The planned alignment of the twin tube tunnel follows closely the existing A303 route, avoiding important archaeological sites, and avoiding intrusion on the view of the setting sun from the stones during the winter solstice. The choice of excavation method, between TBM or an open face SCL, is being left to the joint ventures to select and present in their proposals.

Highways England Project Director Derek Parody said: “We are looking forward to entering into a competitive procurement process, subject to planning consent being granted by the Planning Inspectorate. The joint ventures are of high calibre experience, with a proven history of delivering complex infrastructure projects, and they are keen to be part of delivering this project.

“We are currently assessing the programme timescales,” he continued, “and anticipate awarding the contract for the main works in 2021. We are confident that the project is in the best position to proceed at pace thereafter.”

In his statement, UK Chancellor Sunak said: “The A303 is one of our most important regional arteries and progress of the upgrade project symbolises delay and obstruction. Governments have been trying to fix this since the 1980s. Every year millions of cars crawl along in traffic, ruining the backdrop to one of our most important historic landmarks. So for this project, this government is going to get it done.”

Following a six-month development consent order examination last year, the Planning Inspectorate has sent its report and recommendation to the Secretary of State for Transport for Government approval “We welcome the Government funding commitment for the upgrade and await the decision from the Secretary of State on our development consent order application,” said Parody.

Highways England has launched an 18-month procurement process to find potential contractors and tunnel specialists for the A303 Amesbury to Berwick Down scheme, which passes the World Heritage Site of Stonehenge. The company, responsible for the major A roads and motorways in England, has published its contract notice in the Official Journal of the European Union (OJEU) this week.

The proposed upgrade includes an approximately 3.3km-long twin-bore tunnel underneath the World Heritage Site. This is longer than the 2.9km tunnel previously proposed – a result of optimising the locations of the tunnel entrances to protect heritage and to best integrate the scheme into the surrounding landscape. The tunnel will closely follow the existing A303 route, but a further 50m away from the Stonehenge monument in order to avoid important archaeological sites, and to avoid intruding on views of the setting sun from Stonehenge during the winter solstice.

Highways England Project Director Derek Parody said: “We expect this scheme to be of interest to some of the best construction companies in the world, that want to be part of delivering this transformational project – a scheme that will not only unlock congestion along this vital A303 route, conserve and enhance the outstanding universal value of the World Heritage Site, but also benefit the local and regional economy by providing skills and job opportunities for businesses large and small.”

The OJEU contract notice covers the £1.25 billion main works contract for the construction of the civil, structural, mechanical, electrical and technology components of the tunnel, including the tunnel boring machine, along with the approach roadworks and structures, and the environmental components of the scheme.

The procurement process has started while the Development Consent Order examination continues to progress, in order to be able to start construction on schedule in 2021, providing planning consent is granted. The procurement model is through competitive dialogue, allowing a period of design development and dialogue during the tender phase, when solutions are developed and tested for compliance with Development Consent Order requirements prior to awarding a contract.

This approach allows greater flexibility, with the appointed team able to start work soon after the contract is awarded. Contracts for enabling preliminary work will be procured separately, as part of the total £1.7 billion capital cost of the scheme. Highways England expect the main construction works to start in 2021 and continue for approximately five years until 2026.

The UK Government this week accounted commitment to construction of a 2.9km twin-tube tunnel as part of a 13km upgrade of the A303 road from two lanes of bi-directional traffic to a four lane dual carriageway to eliminate a major traffic bottleneck on the four-lane east-west route in southern England and protect the World Heritage site of the ancient Stonehenge monument.

Fig 1. Preferred route of the proposed 2.9km twin-tube tunnel

In announcing a new preferred route for the estimated £1.6 billion upgrading bypass, Secretary of State for Transport Chris Grayling brought to a close a period of public consultation that the government was forced to conduct to re-examine a previous route that drew fierce opposition from the general public, commentators and UNESCO which lists sites of World Heritage.

The most significant improvements, according to a statement by Highways England, the project owner, include a change to the route through the western half of the World Heritage site and to the location of the western tunnel portal with both now closer to the line of the existing A303 than they were before the consultation.

The preferred route, it states, avoids many important archaeological sites, including newly-discovered barrows just to the east of another regional road, the A360 and avoids the road intruding on the view of the setting sun from Stonehenge during the winter solstice.

Upgrading the A303 between Amesbury and Berwick Down and through the new tunnel will improve journeys on a proposed Expressway to the South West of the UK, ease serious congestion in the area and through the village of Winterbourne Stoke and enhance the setting of Stonehenge by reconnecting it with its surrounding landscape and removing the sight and sound of traffic.

Following the announcement by the Department of Transport, Highways England is developing a more detailed proposal of the preferred route for another round of public comment, as required by the Planning Act 2008, before the final scheme is submitted to Government for development consent. If all goes according to its plan, Highways England aims to carry out the next round of consultation in early 2018 and start construction on the new road and its tunnel in 2021.

Upgrade of the A303 has been particularly sensitive and under planning since 1989 (Table 1). Between Amesbury and Berwick Down, the road passes 165m from Stonehenge with some 24,000 vehicles using the stretch of road daily, twice as much as the single carriageway was designed for. The road and traffic can be seen and heard from the Stonehenge monument, is a high accident rate blackspot and creates high levels of air pollution.

Previous efforts to advance the project have been defeated by public opposition and costs. Given the different routes explored in the past, the Government now believes it has adopted an acceptable alignment and has made money available to move forward. The project however remains controversial with leading personalities in the UK calling the current improved route and upgrade plan "the most brutal intrusion into the Stone Age landscape ever" and saying that the project needed a "complete re-think, not a minor tweak".