Natural England has confirmed Lodge Hill in Chattenden as a Site of Special Scientific Interest (SSSI) for its nightingale population, special grassland and woodland.

A Site of Special Scientific Interest (SSSI) is one of the country's very best wildlife and/or geological sites.

The decision, taken by the Natrual England board at a public meeting yesterday, marks the final step in the designation process after Lodge Hill was notified as a SSSI in March this year.

The site was combined with SSSI land at neighbouring Chattenden Woods to form Chattenden Woods and Lodge Hill SSSI. It is the first in Britain to have the nightingale Luscinia megarhynchos as one of its notified features.

As the government’s conservation adviser, Natural England has a duty to notify SSSIs when it considers an area of land is of special interest for its flora, fauna or geological or physiographical features.

The special interest features of a SSSI are given protection against operations that are likely to damage them - such as the 5,000 homes, shops, offices and schools planned on the old Army base.

Speaking after the Board’s decision, Poul Christensen, Natural England’s chairman, said: “The evidence clearly points to this site being one of the most important strongholds for nightingales in the country.

"Confirming this land as a Site of Special Scientific Interest gives the clearest possible recognition of this."

As well as its important nightingale population, Chattenden Woods and Lodge Hill SSSI is considered to be of special interest for its lowland ancient and long-established semi-natural woodland and its unimproved neutral grassland, both of which are nationally important.

More than 80% of the local nightingale population is distributed across the area proposed to be allocated for development.

The decision to extend the SSSI clarifies the environmental importance of the site but does not determine whether or not development can go ahead; this is a matter for the planning system.

A spokesman for Natural England said: "Natural England will continue to engage with Medway Council, landowners Ministry of Defence and its commercial partner Land Securities to contribute, as appropriate, to the planning process.

"In particular, and in order to contribute to sustainable development, we will consider carefully any proposals for a habitat creation scheme to offset the impacts on the special wildlife of the site, should development proceed."