Highways England are aiming for the Lower Thames Crossing - the proposed multi-billion pound tunnel linking Kent to Essex - to be the "greenest road ever built in UK".

The ambitious 14-mile road project, set to cost £8.2bn, will be built east of Gravesend and is designed to help ease congestion at the Dartford Crossing.

Now National Highways - the government department, formerly known as Highways England, tasked with organising the construction of the tunnel - says it has been designated a 'pathfinder project'.

That means it will work with everyone from engineering companies to universities to develop "innovative ways of building and maintaining low carbon infrastructure".

The announcement comes amid concern from critics of the scheme which said the tunnel will produce five million tonnes of carbon emissions.

At an industry summit to be held today in conjunction with the Thames Estuary Growth Board, called Road To Net Zero Construction, the firms bidding to build the project along with local businesses will discuss how to develop a "green economy" for both Kent and Essex.

Ideas being considered for the tunnel's construction include "removing diesel from its sites by only using hydrogen and electric plant, and looking at alternatives to carbon-intensive materials such as concrete and steel, after which the project will also consider carbon offsetting to address any residual emissions".

Matt Palmer, executive director for the Lower Thames Crossing said: “Our roads play a critical role in keeping people and the country’s economy moving, now and long into our low-carbon future. We want to make the Lower Thames Crossing the greenest road ever built in the UK, and as a pathfinder project we will push the boundaries in construction and show how we and other large infrastructure projects can help the UK reach net zero.

“But we can’t do it alone. We have an ambitious partner in the Thames Estuary Growth Board, and we’re delighted that over 500 local business have already signed up to our SME directory and registered their interest in supporting the project; it’s an incredibly exciting opportunity to develop low carbon innovations that can help them be at the forefront of a new green economy in the region.”

Roads Minister Baroness Vere added: “Exploring carbon neutral construction is crucial to our efforts to decarbonise our transport network and 'build back greener' from the pandemic.

“I hope this groundbreaking proposal will pave the way for other innovative, green solutions to roadbuilding in the future.”

Kate Willard, estuary envoy and chair of the Thames Estuary Growth Board said: “The ambitions of the Lower Thames Crossing team echo our own. Just as they aspire to create the greenest road ever built in the UK, we are striving towards creating the world’s greenest estuary. That is why we partner with and support brilliant projects like these that take an innovative approach to sustainability. This project paves the way for transport infrastructure progress in the UK."

National Highways says it plans to submit an application for a Development Consent Order for the new crossing later this year, once it has held a further round of consultation on revised plans near the river in Thurrock to support the Thames Freeport, and a handful of refinements following feedback from the local community and stakeholders.