National Highways has announced its preferred bidder for a £450m contract as part of a project to create the UK’s longest road tunnel.

If given approval, the Lower Thames Crossing, near Gravesend, would connect Kent and Essex in an attempt to ease congestion at the Dartford Crossing.

It is still subject to approval, but the highways company has revealed Skanksa has become their choice for the multi-million Kent Roads contract.

The deal would mean the southern part of the route, which connects the A2/M2 tunnel approach, and includes almost four miles of new road and structures, would deliver one of the widest green bridges in Europe, a new public park and 12 miles of new or improved pathways for walkers, cyclists and horse riders.

In 2022 the project announced it wanted to have the lowest carbon construction available in the market.

National Highways asked for a minimum of 30% reduction across the project and the bid from Skanska proposes an even lower limit.

Skanska has said it will also try to support National Highways’ plans to recruit 45% of its workforce from within 20 miles by upskilling local people with new qualifications and training.

Lower Thames Crossing procurement director Katharina Ferguson said: “Skanska has a track record of providing innovative low carbon solutions to projects, and leaving a genuine legacy of skills and innovation in the local community.

“We look forward to working together to deliver this desperately needed piece of new infrastructure in a way that pushes the boundaries in low-carbon construction and social value.”

The Kent Roads contract is the second of three major National Highways contracts which will deliver the multi-billion pound crossing, if it is given the green light.

In January 2023, the roads north of the Thames contract was awarded to Balfour Beatty and a separate contract for the tunnels and approaches is expected to be awarded later this year, the highways company says.

National Highways is awarding the contracts ahead of consent possibly being granted for the project to allow its partners as much time as possible to collaborate and carry out the detailed design work that seeks to reduce the impact of construction on the local community and the environment.

The start of construction is subject to funding and consent decision from Government. If consent is granted, the six-year construction period is expected to start in 2026.