London-based Aros Architects have produced early plans to turn World War II sea forts seven miles off the British coast into a luxury hotel and spa.

The unused Redsand Forts in the Thames Estuary near Kent, built in 1943 to defend Britain against a Nazi attack, could become a hotel with executive apartments, where guest can fly in by helicopter.

A similar development took place in 2012 at Spitbank Fort – built in the Solent in the 1800s to protect Britain from a Napoleonic invasion – which is now home to a private island resort with rooftop hot pool, sauna and fire pit. It’s neighbour, No Man’s Fort, has recently opened after being similarly developed.

Aros’ proposed plans are to develop the old Redsand gun towers into a complex with around 40 standard, executive and penthouse rooms.

Guests will arrive by helicopter or hovercraft from St Katherine's Dock in London, Southend-on-Sea, or Whitstable.

They will land at the central ‘hub’ of the hotel, once the old control tower, and access their rooms via glass walkways giving views of the sea below. The health club and spa will be built in a tower known as Bofors.

A heritage museum and its own separate arrival jetty will be developed in the Searchlight Tower to celebrate the historic significance of the site, which was designed by civil engineer Guy Maunsell.

Aros Architect Jenny Fizgerald said: “The scheme seeks to refurbish and celebrate the existing structures. The concept of what we are affectionately calling a ‘rubber ring’, proposes a new central hub around the old ‘Control Tower’, with hotel foyer, restaurant and sun terraces. This hub is linked by glass walkways, in place of the historical bridges, to the Gun Towers which house the hotel accommodation and a health spa within another tower called Bofors.”

Charitable group the Redsands Project is working with Aros Architects and businessman David Marriot Cooper to find a hotel group to lease ownership and back the scheme.

The forts, decommissioned by the Ministry of Defence in 1956, are owned by the Crown Estates.