UK approves tunnel bypass at Stonehenge 14 Sep 2017

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".