Bull Sand Fort, Humber Estuary, East Yorkshire
The larger of two Island forts built to defend the mouth of the Humber during the First World War. The octagonal concrete and steel structure was originally armed with four 6" breech loading guns and four 90cm spotlights. The armoury was upgraded during WWII to include two 6-pounder quick firing guns to help guard against the threat of motor torpedo boats entering the estuary. The fort's remote location has recently attracted a plan to convert it to a drug and alcohol detoxification centre.