National Highways has selected the company that will build the huge tunnel boring machine that will dig the UK’s longest road tunnel – Lower Thames Crossing.

The huge machine will be delivered to site and start work in 2028 with the new road on track to open in the early to mid-2030s.

The machine will be built in Germany by Herrenknecht, which made the machines used to create the Elizabeth Line, the Silvertown Tunnel, HS2 and the Thames Tideway Tunnel. It will be bought and operated by the project’s delivery partner, Bouygues TP Murphy Joint Venture.

At 16.4 metres in diameter the machine will be the largest ever used in Europe and the third largest ever in the world. It will dig two parallel tunnels, each more than twice the size of the existing tunnels at Dartford and big enough for three lanes of 70mph traffic.

The project will double road capacity across the Thames east of London to tackle congestion at Dartford and unlock economic growth by creating a new trade route between the ports of the South East, the Midlands and the North.

Due to the machine’s size – 120 metres long and weighing more than 5,000 tonnes – it will be delivered to site in segments by sea and carried up the Thames and delivered to the Port of Tilbury.

At 2.6-mile-long, it will be the longest road tunnel in the UK. It also aims to be the “greenest” road and have one of the smallest carbon footprints.

Shaun Pidcock, delivery director at Lower Thames Crossing, said: “We are working at pace and are on track to deliver Britain’s greenest road, driving down carbon emissions and protecting the environment as we do so. Choosing our partner to supply the giant tunnel boring machine means real progress on the project – and we’ll put it to work as soon as it arrives on site in 2028.”

The machine will be able to dig through clay and chalk up to 60m below the Thames and will be powered by electricity from renewable sources.

A single machine will be used to dig both tunnels to save money and reduce the project’s carbon footprint. The machine will begin tunnelling near the Port of Tilbury in Thurrock in 2028, before being turned around to create the second tunnel.