Bull Sand Fort under construction: main floor, 30 September 1917

This photograph forms part of a remarkable group of nine images preserved in the Trevitt Collection, documenting the construction of the Humber sea forts during the First World War. Eight of the photographs show Bull Sand Fort, while a ninth records work on Haile Sand Fort (described in some contemporary records as Sandhail Fort). Together, they form an important local photographic record of one of Britain's greatest wartime engineering projects.

Dated 30 September 1917, as recorded on the original negative, this photograph provides a wide view of the main floor of Bull Sand Fort during construction. The massive circular concrete structure is taking shape, with the main floor partly concreted and extensive shuttering and temporary timber structures still in place. Steelwork, timber, construction materials and equipment can be seen across the site, while men work at various levels. Cranes, hoists and other machinery rise above the unfinished structure, emphasising the scale and complexity of the work being undertaken offshore.

The photograph gives a particularly vivid impression of the fort as a working construction site rather than the finished defensive structure that would eventually stand at the mouth of the Humber. The numerous workmen, ladders, temporary platforms and pieces of machinery provide a sense of the enormous logistical effort involved in transporting materials and constructing such a substantial installation at sea.

Construction of Bull Sand Fort began in 1915 as part of Britain's First World War coastal defence programme. Built by C. J. Wills & Sons Ltd. under the direction of Major-General Sir G. K. Scott-Moncrieff, the fort was designed to protect the approaches to the Humber and the strategically important ports of Hull, Grimsby and Immingham. Although considerable progress had been made by the time this photograph was taken, construction continued until the fort was officially completed in December 1919.

The nine photographs in the Trevitt Collection provide an unusually valuable local record of the construction of the Humber sea forts, capturing not only the developing structures but also the men, machinery and materials involved in this remarkable wartime engineering undertaking. Bull Sand Fort and its companion, Haile Sand Fort, remain prominent landmarks at the mouth of the Humber today.

Photograph: The Trevitt Collection Date: 30 September 1917 Location: Bull Sand Fort, Humber Estuary