Cold War defence boom, Pig's Bay, Shoeburyness

The Shoeburyness Boom refers to two successive defensive barriers across most of the Thames Estuary in the mid-20th century. As to the part perpendicular to the north shore most of the latter incarnation remains, and its nearest concrete mooring/patrol point 600 metres south. A 2 km stretch, this is designated a scheduled monument and marks the western edge of MoD Shoeburyness firing range, a restricted area. The rest was taken up in the 1960s.

The first guise was built in late 1939, the first months of the Second World War, mainly to protect shipping and the capital from attack by submarines, mines and surface vessels. It was dismantled. The second was built between 1950 and 1953 to forestall access to the estuary by Soviet submarines during the Cold War.