A sprawling 128-hectare complex of earthworks, crumbling foundations and overgrown tramway beds on the English coast has been revealed in striking new aerial footage as one of the last surviving physical records of a forgotten wartime explosives industry that once employed thousands and claimed the lives of workers in a string of catastrophic accidents.
The site, known as the Cliff Explosives Works, sits on marshland that was first developed in the early 1890s by the Hay Merikson Company before being taken over and massively expanded by Curtis and Harvey, eventually becoming HM Cordite Factory Cliff during the First World War. New analysis of the remains, presented in a detailed video survey of the site, shows that nearly every stage of the explosives manufacturing process can still be traced across the landscape, from the earliest gunpowder blending houses to the enormous cordite drying stoves thrown up in a frantic wartime expansion.
What makes the site extraordinary, according to the survey, is not any single surviving building but the sheer scale and organization of what remains. Rather than a conventional factory with clustered structures, the works were deliberately scattered across the marsh, with buildings separated by wide distances and surrounded by massive banks of earth known as traverses, designed to absorb the blast if a neighboring structure exploded.
Those traverses are among the most visible features from the air. Circular and rectangular earthworks dot the landscape, some rising more than three meters high, forming blunt but effective barriers between buildings that housed volatile materials. The survey notes that the earth banks around one structure, nicknamed Nitroglycerin Hill, rise to roughly twice the height of surrounding traverses, a clear indication of just how dangerous the work inside was.
The oldest surviving structures on the site, identified as structures one and two, date to the original Hay Merikson works of the early 1890s. At that time, gunpowder manufactured in Scotland was brought south to be blended, packed and stored. Structure one later became known as Magazine Number Two, while structure two was designated Blending House Number Twelve.
Both were reused repeatedly as the factory grew and evolved over its roughly thirty-year history.
Nearby, rows of smaller earthworks have been identified as cartridge filling huts, where workers handled the finished explosive material in lightweight wooden sheds. Those buildings have long since vanished, but their platforms and foundations remain, along with the deliberate earth banks piled around them. The survey notes that this area is the most likely location where two female workers were killed in 1908, though the exact building where they were working cannot be pinpointed.
The video survey, which draws heavily on a detailed archaeological study of the site, traces the production process from north to south and from west to east, showing how raw acids and glycerin were brought together to produce nitroglycerin before being washed, mixed with gun cotton and eventually transformed into cordite, the propellant that powered British munitions through the First World War.
At Nitroglycerin Hill, identified as structure 31, acids and glycerin were combined in a lightweight two-story building surrounded by an earthwork rising about 3. 2 meters. Historic England records associate the location with a serious incident in 1911, though surviving accident records place the actual explosion at a final wash house nearby rather than in structure 31 itself.
Structures 30 and 32 are considered potential nitroglycerin wash houses, where excess acids were removed from the newly produced explosive.
Further south, the survey identified an area devoted to acid handling and the manufacture of gun cotton. The precise function of every surviving foundation could not be determined, but archaeologists concluded that structures 39 and 63 may have been used for gun cotton nitration or for washing and pressing the material. Other nearby remains were likely associated with acid storage and possibly power generation.
The site also included administrative buildings and private residences, including the manager’s residence, which the survey describes as having an incredible history of its own. Not every structure was devoted to the dangerous work of explosives production, and sections of the complex appear to have been reserved for paperwork, supervision and daily life.
At the southern end of the site, a regular pattern of small earthworks has been interpreted as cartridge filling huts, structures 59 through 93, arranged neatly and separated from one another. Nearby, structure 95, a small barrel-vaulted building, was identified as an expense magazine, a small store for particularly sensitive explosive components needed during the day’s work.
Two large circular hollows to the southwest, structures 103 and 104, have been tentatively interpreted as the remains of exploded nitroglycerin buildings. The survey notes that it is unclear what accidents may have occurred there, but that their isolation from the rest of the site is unusual and suggests they were deliberately placed far from other structures.
To the north, a distinctive Y-shaped group of buildings, structures 106 to 114, was devoted to the manufacture of cordite. Structure 107 may have been an incorporating house, while structures 108 and 109 were interpreted as cordite press houses. Structure 110 appears to have housed a pump and hydraulic accumulator, providing the power needed to force cordite dough through dies to produce the long cords from which the material takes its name.
Alongside the Y-shaped group stood structure 129, a range of ten cordite drying stoves later altered to contain twenty acetone recovery stoves. During that conversion in 1914, a laborer named John Gear was killed. According to the survey, Gear had been working with a chisel that may have encountered a tiny film of nitroglycerin, igniting a devastating explosion.
In the center of the site, structures 139 to 152 were associated with gun cotton drying, while structures 143 to 154 were groups of cordite drying stoves. Gun cotton needed to be dried before it could be incorporated into cordite, and the finished cordite required drying as well, a process that consumed enormous amounts of space and labor.
The First World War transformed the site beyond recognition. What had been a largely organic factory, developed piecemeal around the marshland, was expanded dramatically to the east, becoming HM Cordite Factory Cliff. The wartime section is visibly more regimented and efficient, with long rows of identical structures laid out in strict grids.
Structures 267 through 283, an incredibly regimented lower area, appear to have been gun cotton drying stoves. The sheer number of them compared with the few in the original factory illustrates how massively production was expanded after the demand created by the war.
Structures 256 to 263 were cordite paste mixing houses, where nitroglycerin and gun cotton were brought together. The survey describes this as probably one of the most dangerous places in the entire factory. Once mixed, the resulting paste continued through the production line, eventually becoming finished cordite.
The flat remains of structure 251 were the incorporating house, where cordite paste was further processed with acetone and mineral jelly to create cordite dough ready for pressing. Structures 246 and 247 were the cordite press houses, each containing nine press positions with hydraulic machinery forcing the dough through dies to produce long cords of propellant. Structures 248 and 249, just outside, housed the hydraulic accumulator and pump house that powered the presses.
Structures 244 and 245 belonged to the acetone recovery system. Structures 240 and 241 each contained thirty stove compartments, while structures 244 and 245 were larger versions with fifty-eight compartments each. Rather than allowing valuable acetone to evaporate away, the factory recovered it for reuse, a clear sign of the industrial scale of the wartime operation.
The most unmissable section of the expanded factory from the air is the final stage of cordite production, a huge area where buildings were separated by far more space than in the old factory. Smaller structures among them were cordite blending houses, where cores of the same diameter were brought together into batches. The rigid, regimented buildings with four distinctive chambers were more cordite drying stoves, each containing four drying compartments where almost-finished cordite sat until every trace of moisture was removed.
Once dried, the cordite was moved into magazines and left Cliff, eventually finding its way to the front lines and to whatever unlucky recipient the war had in store. The survey notes that every step of the process can still be traced across the landscape, from structure to structure, from building to building, from ruin to ruin.
That continuity, according to the survey, is what makes the Cliff Explosives Works one of the best surviving examples of a wartime explosives factory in the country. The earthworks, foundations, tramway beds and traverses form a physical archive of an industry that consumed vast quantities of land, labor and human life, and that has largely vanished from public memory.
The video survey is presented as a companion to an earlier overview of the site’s history and the many accidents that occurred during its roughly thirty-year operation. Together, the two pieces document not only what the factory produced but how it was built, how it was organized and how it was repeatedly reshaped by the demands of war and the constant threat of explosion.
For historians and archaeologists, the site remains a rare and valuable record. Old site maps listing the function of each building may exist somewhere, but the survey was unable to locate them, leaving the archaeological study and informed guesses as the best available sources for understanding what each structure was used for.
What survives is a landscape of mounds, hollows, platforms and earth banks, silent evidence of a place where acids and glycerin were brought together, where cordite dough was forced through dies, where acetone was recovered and reused, and where workers, including at least one laborer killed with a chisel in 1914 and two women killed in 1908, carried out some of the most dangerous industrial work of their era.
The aerial perspective makes clear what ground-level inspection can obscure: the sheer size of the operation, the careful separation of buildings, the network of tramways that moved materials from stage to stage, and the massive wartime expansion that turned a modest marshland factory into a national munitions plant. The remains may be overgrown and fragmentary, but the story they tell is still legible across the landscape.