A conservation charity has launched a campaign to stop a major extension of a ragstone quarry which it says could destroy a swathe of ancient woodland.

The Woodland Trust’s campaign has already generated more than 7,000 letters of objection to Kent County Council’s draft Minerals and Waste Plan, which, if it it was agreed, would allow the ragstone quarry run by Gallagher Aggregates Ltd in Hermitage Lane, Barming, to more than double in size.

The trust said: “The proposed quarry extension could ravage more than 50 hectares of Oaken Wood, an ancient woodland.

“It’s a shocking and short-sighted proposal that completely disregards the national commitments to tackle the nature and climate crises.

“The loss of ancient woodland from this scheme could be greater than the losses from HS2 and the Lower Thames Crossing combined.

“It is the biggest single development threat to ancient woodland in England for decades.”

The trust said that in 2013, an extension to the quarry was approved by government and as a result the quarry now occupies 32 hectares of what was once precious ancient woodland.

But it points out that since then, protection for ancient woodland has been strengthened in planning policy.

“The proposals aren’t clear on exactly how much ancient woodland will be taken,” the trust’s statement continued.

“Our analysis suggests at least 50 hectares is likely to face the chop, with much more exposed to serious long-term damage and deterioration. That’s equivalent to more than 70 football pitches.

“We’re appalled that such an outrageous amount of destruction is even being considered.”

The proposal forms part of KCC’s new Mineral and Waste Local Plan, which is out to public consultation here. People have until July 25 to give their views.

The trust is urging people to oppose the plan and has made it easy to do so by drafting a letter for them to use which they can find online here and send to KCC by an attached link.

KCC proposes to allow Hermitage Quarry to expand by 96 hectares, to allow Gallagher to extract a further 20 million tonnes of ragstone.

Officers said there is an expected shortfall of 17.4 million tonnes in the provision of hard rock extraction over the plan period up to 2039.

KCC had previously carried out a “call for sites” inviting landowners across the county to put forward suitable plots for ragstone extraction, but only one came foward – Gallagher’s.

The company proposed an extension to the south and west of its existing quarry.

It says the extension would ensure the future of 190 jobs at the quarry and points out that ragstone is an essential material for the repair of many heritage buildings.

It says that it has a proven record of restoring land to an enriched biodiversity standard once the quarrying is finished.

It said: “We are exploring options for the ongoing preservation of the ancient woodland soils, to ensure a biodiversity net gain which preserves the soil quality and local biodiversity for future generations."

Gallagher says the extension to the quarry could supply ragstone at a rate of around 900,000 tonnes a year.

At the end of its life, the quarry would be restored to its original levels with inert materials and be returned to mixed native woodland and meadow.

Vehicle access would continue to be from Hermitage Lane.

The site is within the parishes of East Malling and Larkfield, Ditton and Barming, and straddles the boroughs of both Tonbridge and Malling and Maidstone.

Cllr Tony Harwood (Lib Dem) said: “I campaigned alongside many local people to ensure that the National Planning Policy Framework contained effective protection for ancient woodland and other irreplaceable habitats.

“Little did I know that the first big test of this policy would be in Maidstone.

“The scale of ancient woodland destruction proposed is immense and if allowed would be the largest area of ancient woodland lost in the British Isles for many decades.

“The promoters of the quarry extension are making much of the fact that most of the wood was replanted with sweet chestnut to produce poles for the hop industry in the 18th and 19th centuries.

“That said, many native trees and shrubs still flourish across Oaken Wood, including pedunculate and sessile oak, hornbeam, hazel, silver birch, common hawthorn, dogwood, rowan, dog rose and holly.

“However, an ancient woodland is the sum of its parts and it is the undisturbed soils and their biome that contain the real wonder of ancient woodland.

“Significantly, it is probably the presence of the broadleaved and deciduous sweet chestnut, that has protected the wood to date by giving it a commercial value that has prevented it from being cleared and ploughed-up for agriculture.

“The presence of sweet chestnut has also contributed towards the remarkable biodiversity of the wood, historically, the best site in Kent for breeding nightjars.

“This is because active rotational coppice management has meant that all important structural diversity has been maintained over the centuries.

“A further key concern is the impact on Net Zero objectives should 50 hectares of ancient woodland be destroyed for a quarry extension.

“The quantity of carbon sequestered by the undisturbed woodland soils and within the many thousands of trees is immense.

“Such an unprecedented loss of ancient woodland would be of national policy significance in terms of the precedent it could set and its impact upon wildlife and climate.”

Cllr Harwood called for the Secretary of State to step in to “ensure an appropriate level of national policy scrutiny and scientific oversight”.

He said: “Too much is at stake for all of us if we get this wrong.”

The quarry extension is also being opposed by the Green Party.

Campaigner Rachel Rodwell has aready collected a petition of 400 signatures against the plan which she has handed in to KCC.

She said: “There is an ecological emergency unfolding around us yet KCC and Gallagher seem to think it is quite reasonable to destroy a huge swathe of ancient woodland for profit and pretty stones for houses and aggregate for more roads.

“Ancient woodland cannot be replaced. It takes over 400 years for the soil biome to mature. It is protected as it has a level of diversity not seen in new woodland.

“With the loss of 70% of species during the past 50 years, this plan does the opposite of what the world needs. If we are to ensure a future for our children we must start planting forests, not destroying them.”

Lance Taylor, chief executive at the Gallagher Group, said: “It is important to clarify that only part of the area that has been identified at this early mineral plan review stage is designated as Plantation on Ancient Woodland Site (PAWS).

“Gallagher Aggregates has established a proven and well-respected restoration and biodiversity enhancement plan at Hermitage Quarry.

“If the identified site is allocated in the new plan, we are committed to replacing the low-value introduced species that are currently present with a more diverse mix of higher value native species in line with our current approved practices.

“This approach ensures not only greater long-term carbon sequestration but also a significant biodiversity net gain, which will contribute to the preservation and enhancement of the local eco system.

“The continuation of Hermitage Quarry is crucial in supporting Kent's Mineral Plan. As the sole provider of crushed rock in the South East of England, Gallagher Aggregates contribution is of utmost significance.

“Failing to increase the supply of Kentish ragstone would lead to the increased importation of rock from other sources, resulting in diluted heritage, increased carbon footprint and detrimental impacts on local jobs and supply chains.

“At the core of this debate lies the challenge of striking a balance between conservation and development.

“Gallagher Aggregates has demonstrated its commitment to environmental stewardship along with responsible resource extraction providing a locally sourced, sustainable mineral to Kents built environment.”

Jack Taylor, the Woodland Trust’s lead campaigner, said: “Ripping up more wooded habitat – that provides such vast benefit to climate, nature and people – is senseless.

“Combined with the scarce amount of ancient woodland remaining, it’s glaringly obvious that Oaken Wood must be spared the axe.

“We are asking people to join us in telling Kent County Council just how outrageous this plan is.”