The mega-project will be the country’s largest road scheme since the M25 was built 35 years ago and will have a major impact on the civil engineering industry.

But despite development consent being granted today, financing for the 14-mile roads and tunnel project running under the Thames has still to be agreed.

The government is currently exploring private finance options for the project rather than 100% public purse funding as originally planned.

It is understood to be looking at the regulated asset base (RAB) model used on the Thames Super Sewer for the project.

Today National Highways said it believed construction could start as early as 2026, with the new road expected to open in the early 2030s.

Matt Palmer, National Highways executive director Lower Thames Crossing, said: “We are shovel ready and have our delivery partners on board, and today’s decision allows us to work with government on funding and start the detailed planning that will let us start construction as soon as possible.”

Before main construction gets underway, the project and its three delivery partners will work with local authorities, landowners, and stakeholders to refine aspects of the design to further reduce the impact of construction on the local community and environment, and embed new and emerging low carbon technologies and materials.

Over the coming months, they will also carry out archaeological, ecological, and topographical surveys, as well as further ground investigations to prepare the detailed design and construction plans.

The National Highways project is the first in a new generation of projects that will accelerate the construction industry’s move to net zero by using fuels such as hydrogen to power its construction fleet and only using low-carbon concrete and steel.

This pioneering approach to carbon has cut the project’s estimated construction footprint by around half so far, with a target to achieve a 70% reduction. The new blueprint for low-carbon construction created on the project is already being replicated across other sectors ranging from nuclear and water to rail and aviation.