The Highways Agency has awarded a £19m contract to Birse to build motorway slip roads to a new service station on the M25.
Work building the new service station and hotel between junction 9 and 10 at Cobham in Surrey has just got underway.
To complete the scheme, Birse will build link roads from both sides of the carriageway, and an underbridge running beneath the M25.
Originally, the tunnel section was to be built as a box section but Birse has opted for a phased cut-and-cover approach.
To ensure journey time impacts are kept to a minimum there will always be a requirement that during daytime hours there will be 4 lanes available for traffic. It is expected that there will be a reduced speed limit, for safety reasons, of 50 mph in each direction.
Birse beat rival bidders Carey, Kier and Bam to the contract, which was let by the Highways Agency on behalf of the developer Swayfields.