A3 Hindhead Tunnel

We constructed the longest under-land road tunnel in the UK, protecting an important area of scientific interest and returning site to its natural roots.

As part of a 6.8km dual two-lane carriageway, the £371 million Hindhead tunnel was designed to relieve local traffic. The site was also responsible for returning The Devil’s Punchbowl, a site of special scientific interest, to its natural state.

Careful consideration

We were involved in the scheme at a very early stage to prepare the design and site planning. This helped us build in cost effective innovation from the start of the project as well as ensuring all environmental concerns were addressed at the right time.

One of the first actions was to remove the wildlife from the construction site, a process that saw 171 reptiles including slow worms, adders and lizards carefully moved to suitable locations. The local population of dormice, badgers, deer, foxes and rabbits were encouraged into new homes.

Thinking ahead

The project is ‘tree neutral’, with more than 2,173 tonnes of timber removed and replaced by more than 200,000 native-species trees and shrubs. 330,000 cubic metres of earth was reused as embankments, in landscaping and noise-reduction banking.

Once the tunnel was opened, the relevant part of the existing A3 was closed and returned to heathland.


  • 2012 Overall winner, ICE Thames Valley Engineering Excellence Awards

  • 2011 Preservation Award, Tunnels and Tunnelling Awards


dual two-lane carriageway and tunnel


average local employment rate achieved