Bull Sand Fort: Humber Estuary's First World War stronghold up for auction

A fort that was built in the Humber Estuary to defend the country against attack in the First World War is being auctioned off.

The grade II listed sea fort was constructed between 1915 and 1919, although the works were not fully completed until after the war had ended.

A listing by the auctioneer Savills said the structure is reinforced by concrete and with 12 inches of armour designed to withstand gunfire on its seaward side.

It described the fort as "in need of refurbishment".

A spokersperson said: "Now, with an imaginative buyer and the right planning consents, [it] could be refurbished and transformed for a number of uses, such as a high-end hotel, restaurant, Airbnb, grand design-style personal dwelling, retreat or a tourist attraction."

Bull Sand Fort, and its smaller companion fort on Haile Sand, 3.75km to the south-west, guarded the approaches to the Humber with gun batteries and an anti-submarine net of steel mesh stretched between them across the mouth of the estuary.

The fort includes three floors, with a basement and magazine below sea level, and a central two-storey observation tower. It has a balcony and jetty.

During the Second World War it was armed, besides the usual small and rapid-fire weapons, by two six-inch guns and two six-pounder guns. It had enough accommodation for a garrison of 200 men.

The fort was decommissioned in 1956.

The virtual sale is due to take place on 19 July.