Revised plans for the Lower Thames Crossing could see large swathes of farmland used to soak up pollution from the new tunnel.

National Highways has revised plans to build the £8.2bn new road, which will link Kent with Essex via the River Thames, and claim it will be the “greenest road ever built in the UK”.

But in its latest consultation proposals, the transport body has proposed taking areas of farmland to compensate for nitrogen emissions from traffic.

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

National Highways says the additional land is needed to mitigate nitrogen from exhaust fumes which falls from the atmosphere onto surrounding land.

Two parcels of land totalling approximately 111 acres have been identified in Thurrock, Essex, to offset the impact of exhaust fumes, the Local Democracy Reporting Service reports.

Part is publicly owned, while an area to the west of the earmarked land is private farmland.

Both are located to the south of the A13 in Southfields and are close to designated sites and existing woodland that are impacted by nitrogen deposition.

To create a greater area of protection, National Highways says woodland would be allowed to grow naturally in these former farmland areas and additional trees and shrubs would be planted.

Mark Bottomley, development director for the project, said if possible, these areas would be made accessible to the public.

“As part of our efforts to address the impacts of the Lower Thames Crossing on the environment we’re are proposing to provide around 617 acres for new wildlife habitats across four sites near to the route of the proposed new road," he explained.

“As well as providing new wildlife habitats and areas of tree planting, if possible, these areas would be made accessible to the public providing new open space.

"We are consulting on this now, as there have been changes in the way the vehicle emissions are assessed for their impact on sensitive designated habitats, and we have worked very closely with Natural England and other environment agencies to update our plans and improve our environmental mitigation.”

A public consultation on proposed changes to the multi-billion-pound project is underway.

Proposed changes include more public open space to the east of the tunnel entrance in Gravesham, connected to Chalk Park – the proposed new public park overlooking the Thames.

There are also plans for better bridleway connections around the A2 junction and the A226 in Gravesham.

The announcement comes amid concern from critics of the scheme who claim the tunnel will produce five million tonnes of carbon emissions and won't solve the long-term traffic issues.

Campaigners from the Thames Crossing Action Group say they are still examining lengthy documents published for a new public consultation and will make a statement once they have done so.

An 11th hour decision was made to the pull the application in 2020 after it became clear the Planning Inspectorate, the government's independent planning arm, was poised to reject the proposals.

The route, which has been in discussion for more than 10 years, is scheduled to open by 2030.

A further round of consultation is currently being held to support the Thames Freeport, and a handful of refinements following feedback.

Natonal Highways says a a fresh planning bid for a development consent order for the new crossing is expected later this year.