Highways England has revealed details of work being carried out to protect and enhance the environment surrounding the A21.

The organisations says it is creating 180,000 square metres of new woodland, preserving a listed barn and protecting wildlife are among the activities that are taking place.

The work is being carried out as part of a major development of the A21. A 2.5 mile section of the road between Tonbridge and Pembury is being upgraded from single to dual carriageway, adding a lane in each direction, upgrading junctions and improving the road layout.

The £70m road scheme hopes to make journeys safer, faster and reliable and bosses say it will deliver an eightfold return on investment for the economy.

However, the Woodland Trust claims Highways England is painting a misleading picture of the work it is carrying out.

Austin Brady, Woodland Trust conservation director, said: "Highways England does not fully acknowledge the loss of irreplaceable habitat. A stated aim within Highways England’s Biodiversity Action Plan is ‘no net loss of biodiversity’ but when a project involves the loss of irreplaceable ancient woodland, as this does, it is impossible to say that aim has been achieved.

"At this site, 9 hectares of ancient woodland – important for its trees, wildlife and hugely valuable undisturbed soils – was destroyed. Highways England’s work to reuse or translocate ancient woodland soils is only a salvage operation at best, with little evidence to support its long-term viability.

"Specific methods must be used for it to be worthwhile but previously agreed timings and processes have not been followed by Highways England in this case, which is disappointing to say the least.”

Upon releasing details of work, Highways England project manager Anne-Marie Palmer, said: “Improving the A21 between Tonbridge and Pembury will deliver real benefits for people living and working in Kent.

"Not only are we improving the road for drivers, we are also making sure that the environment is protected by the improvements. We recognise that that the A21 runs through exceptionally beautiful and protected countryside, and has significant cultural heritage.

"That’s why we’re ensuring that we are protecting the environment and preserving some of the history of the area.”

Although the improvements involve clearing around 9 hectares of existing woodland to allow the widened road to pass through, the project team say they are replacing it with double that amount of woodland creation.

Ancient soils and rootballs, along with additional planting, are being moved from the cleared area to the new location to ensure that the species mix of the woodland is preserved. These areas will be managed for 25 years.

In addition, 26 hectares of existing woodland will be enhanced and also managed for 10 years while the new planting becomes established.

A grade II listed building was carefully removed from the side of the A21 and is now in storage waiting to be rebuilt in an archaeological heritage museum.

Various species have been protected, including dormice and the great crested newt.

Meanwhile, construction continues to improve journeys on the A21 for the tens of thousands of drivers that rely on this vital route.

In the next few months, it is expected that the project will move into the next phase with work starting on the new Longfield junction near Pembury.