After a decade in development, plans to transform a historic military site into 635 homes are coming to fruition.

Fort Halstead, at Halstead near Sevenoaks, sits on the crest of the North Downs, making it the ideal defensive position to protect London in the event of foreign invasion.

At least that was the thinking of the Secretary of State for War, Edward Stanhope, who commissioned the fort to be built in the late 1890s.

Since then, it has seen life as the secret establishment for early work on the development of Britain’s nuclear bomb, delivered to the Royal Air Force in 1954, and more recently as a Defence Science and Technology Laboratory, which among other duties was tasked with examining crash debris such as those from the December 1988 Lockerbie bombing.

The site was once one of Sevenoaks’ largest employers, at one time providing 1,300 jobs, but the government announced in 2015 it would start running down the site, and sold it in 2017.

Various plans to redevelop the area have been proposed since as early as 2014, but finally housebuilder Barratt David Wilson Homes has purchased the site from the Merseyside Pension Fund and will go ahead with plans to build 635 homes under a grant of planning permission made by Sevenoaks council in December 2023.

The scheme will allow for 20% of the new homes to be affordable. They will be designed around “a village centre” with shops and community buildings.

The new estate will include an innovation hub for businesses, while listed buildings on the site will be refurbished.

The 19th century fort and its bunkers will be retained and opened as an historic interpretation centre for the public.

The site is within the Green Belt, within an Area of Outstanding Natural Beauty (AONB) and contains areas of ancient woodland.

William Walsh, MD at Barratt David Wilson Kent, said: “Our plans for transforming the site represent so much more than just delivering hundreds of new homes. We will reinvigorate the past while creating a forward-looking, sustainable development for the future.

“Fort Halstead is truly a once-in-a-lifetime opportunity to develop something unique on a site with a rich – and sometimes top-secret – heritage.”

“The economic hub will continue that history of innovation, while we also restore the landscape and protect the surrounding ancient woodland.“

The project will be brought forward in a number of phases, with the company promising further public consultation at every stage.

Mr Walsh said: “This is just the start of our conversation with the community.”

The site was purchased in 2017 by the Merseyside Pension Fund, who saw it through the planning process stage.

A spokesman said: “We wanted to bring forward a mix of quality homes, community buildings and amenities in this sought-after area. We are pleased Barratt David Wilson Homes will be able to deliver to our expectations."

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The approved planning application can be viewed on the Sevenoaks District Council website, under planning application number 19/05000.