Delivering the UK’s longest under-land road tunnel
Balfour Beatty constructed the UK’s longest under-land road tunnel, delivering a landmark infrastructure scheme that relieved congestion while protecting and restoring an environmentally sensitive landscape.
The £371 million Hindhead Tunnel forms part of a 6.8km dual two-lane carriageway designed to divert traffic away from the village of Hindhead. Crucially, the scheme enabled the restoration of the Devil’s Punchbowl — a Site of Special Scientific Interest (SSSI) — returning the landscape to its natural state and reconnecting habitats previously divided by the A3.
Environmental stewardship from the outset
We were involved at an early stage of the project, enabling us to shape the design and construction approach from the outset. This early engagement allowed cost-effective innovation to be embedded into the scheme while ensuring environmental considerations were addressed proactively and comprehensively.
One of the first phases of work focused on protecting local wildlife. A carefully managed relocation programme saw 171 reptiles – including slow worms, adders and lizards – safely moved to suitable habitats. Local populations of dormice, badgers, deer, foxes and rabbits were also encouraged to relocate to newly created environments beyond the construction zone.
dual two-lane carriageway and tunnel
average local employment rate achieved
Building with the future in mind
The project was delivered as ‘tree neutral’, with more than 2,173 tonnes of timber removed and replaced through the planting of over 200,000 native trees and shrubs. In addition, 330,000 cubic metres of excavated material was reused on site to form embankments, landscaping features and noise-reduction barriers, significantly reducing waste and vehicle movements.
Following the tunnel’s opening, the relevant section of the existing A3 was closed and the land successfully restored to heathland, allowing nature to reclaim the landscape and significantly improving the area’s environmental value.
Awards and recognition
- Overall Winner – ICE Thames Valley Engineering Excellence Awards (2012)
- Preservation Award – Tunnelling and Tunnelling Awards (2011)