Wartime legacy - the Thames Estuary Sea Forts

Two incredible linked structures on stilts still stand eerily way out in the Thames Estuary, halfway between Essex and Kent, looking like something out of H.G. Wells' War of the Worlds. Known as the Maunsell Army Sea Forts, they are actually a rusting reminder of the Second World War, and the nation's preparations to deter invasion.

Part of the Thames Estuary defence network, a network of three anti-aircraft tower-fort complexes were originally constructed in 1942, with each fort consisting of a cluster of seven stilted buildings surrounding a central command tower. When operational, catwalks connected the buildings. Built on land and then transported out to sea, the forts were designed by Guy Maunsell, a British civil engineer with a special interest in the use of concrete. Originally there were three of these forts, but only two remain: the Red Sands and the Shivering Sands forts. The Nore Army Fort was badly damaged by both a storm and being struck by a ship and was dismantled in 1959-60.

After their successful wartime career, the forts were decommissioned in the 1950s, and In the 1960s and 70s, the remaining abandoned forts were taken over as pirate radio stations. All of them are now derelict.

Of the seven connected forts built as the Red Sands installation, one has been lost, hit by a Norwegian boat in 1963.

The Shivering Sands Fort was occupied by the artist Stephen Turner for 36 days in 2005, roughly the same amount of time a WWII serviceman would have spent at the fort. He described the project as an experiment in isolation and wrote a blog and a book about the project. In 2008 band The Prodigy filmed a music video at Red Sands.

The closest place to see the sea forts is Whitstable, about an 8-mile boat trip. They can be seen from the coast in clear weather, and the nearest location on the other side of the Estuary is Shoeburyness.

It is possible to take a closer look at the sea forts from the Greta sailing barge out of Whitstable.