Factory complex with railway siding shown but not named. Large structures in Toton parish, welfare buildings (including hospital and institute) in Chilwell parish. Several of these still stand.(1)

On 20 August 1915 Godfrey Chetwynd was given the task of designing, building and superintending the running of a factory to fill large calibre shells with Amatol. The Chilwell site was apparently selected as it was close to a railway line from which a siding connection could be constructed, and sheltered from surrounding areas by hills. From the start, women were employed. This may have been another reason for the choice of location, as there was a tradition of women working in local textile factories in the nearby towns. Owing to their exposure to the explosives, many women's skin turned yellow, and they were known as the "Chilwell Canaries" or "Canary Girls". A substantial part of the National Shell Filling Factory was destroyed in an explosion of eight tons of TNT on 1 July 1918. In all 134 people were killed, of whom only 32 could be positively identified, and a further 250 were injured. The unidentified bodies are in a mass grave in St. Mary's Church, Attenborough. The blast was reportedly heard twenty miles away. The factory returned to work for the war effort the next day, and within one month of the disaster reportedly achieved its highest weekly production. At the end of the war, in 1919, the site became a Royal Army Ordnance Corps (RAOC) storage depot. (2)

At the outbreak of the Great War the principal British shell filling was picric acid or lyddite. Trinitrotoluene or TNT had been used by the Germans since the beginning of the century but was only manufactured by a few British factories prior to 1914. Experiments showed that relatively expensive TNT could be mixed with ammonium nitrate, which acted as a diluter, when used as a shell filling this mixture was known as amatol. The factory at Chilwell was conceived with the twin aims of meeting the demands of the army on the western front for vast quantities of artillery shells and to fill these shells with the novel product - amatol. The factory was known as National Filling Factory No.6 Chilwell. It was one of the most important filling factories in the country, it filled over 50% of the 60-pounder and 15-inch shells used during the war, which numbered 19,250,000 shells. In addition it also filled naval mines and aerial bombs.
Responsibilty for the construction and operation of the new factory was given to Lord Chetwynd, a man with no previous experience in handling explosives. The site at Chilwell was selected due to its central location in the country where explosives manufactured in the north and midlands could be brought together, filled and then moved south to the embarkation ports. The site at Chilwell also offered open farm land on which to build the factory and a ready supply of labour with Nottingham laceworkers laid off after the outbreak of war. As with many processes associated with the manufacture and handling of explosives novel solutions were required to meet new problems. The solution to the problem of filling shells with amatol arrived at by Lord Chetwynd was one of the most individual and idiosyncratic. TNT and ammonium nitrate were supplied to the factory by rail from different chemical works and were stored before mixing. Ammonium nitrate is highly hydroscopic and before processing it needed to be dried and crushed. In the design of the plant he adapted coal crushing, stone pulverising, sugar drying, paint making, sugar sifting, flour milling and bread making machines to the processes of preparing the ingredients and mixing the amatol.
In operation ammonium nitrate and pure TNT were delivered to the factory by rail and kept in storehouses on the southern side of the factory until needed. After the ammonium nitrate had been dried, it and the TNT passed to two separate multi-storey mill buildings, similar in design to contemporary flour mills. The ingredients were then milled and sifted and allowed to fall by gravity through the buildings. The prepared powders then passed to the Mixing House where they were combined in the correct proportions. The powdered amatol was then moved along a covered passage to the Press Houses, in the meantime empty shell were brought from the Empty Shell Store at the base of the hill. These were then filled with the powdered amatol before the contents were compacted under hydraulic pressure. The filled shells were then moved down the hill to the Filled Shell Store ready for dispatch.
Chilwell was the scene of the worst accidental munitions explosion of the Great War in Britain when on 1 July 1918 the ammonium nitrate plant exploded resulting in the loss of 134 lives. A monument (SK 50868 35201) comprising a truncated pyramid set on a square stepped plinth surmounted by an obelisk commemorates those who died in this explosion and other accidents during the war. It is surrounded by a chain link fence supported on upright shells. The factory was, however, soon rebuilt and was almost complete by autumn 1918.
After the end of the war the factory was partly dismantled, but a number of buildings were retained for use as a military stores depot. It retained this role throughout the second world war and up to the present day.
Within the present depot a number of building from the Great War survive adapted to new uses. On entering the depot along Chetwynd Road on the north side of the road is alarge single storey building with stone faced piers (building 125)(SK 5097 3526), on the front elevation is a carveds tone plaque enscribed `NSFF Chilwell' with the crossed `C' monograph of Chetwynd of Chilwell in its centre. To its west, also on the north side of Chetwynd Road is the monument to those killed in 1918, located on the site of the ammonium nitrate melt house where the explosion took place. The largest surviving building is the former shell store (building 157)(SK 506 349) this is steel framed with brick infilled external walls. Its floor area covered nearly 9 acres and it could hold upto 600,000 filled shells and 100,000 empty shells. During the Great War it was served by a system of overhead cranes, the holes for the guide rails may be seen in the roof girders. To its north is building 137, the former medical centre (SK 5070 3525). This is a brick, single storey ten bay structure with a tall central tower perhaps originally holding a water tank. A notable feature of this building is a red cross device picked out in brick on the central tower and end gables. Also surviving from the factory is along tunnel, with a gated entrance at its southern end and a set of steps leading down into it from a circular brick cupola at its northern end (SK 5076 3551). At the northern end of the factory and at its highest point a level terrace was created for the Press Houses (where the amatol filling was pressed into the shells). Although the press Houses have been demolished this terrace remains and is occupied by a long narrow building numbered 102.
The most impressive survival from the factory is the former administrative building and Chetwynd's house, Woodside House (building 101)(SK5094 3545). This is brick built two storey structure, with the brick work on the corners laid to represent ashlar columns, decorative ironwork also survives some using crossed `C's as a motif, the building is surmounted by clock tower. The building is now used as the officer's mess. Other smaller structures and features, such as monographed lamp posts, also survive but it was not possible to locate all of these during this brief escorted visit to the depot. (2-7)

Historic England, 2021, National Record of Historic Environment (Digital archive). SNT5271.

<1> OS, 1939, 1:2500, County Series 1939 (Map). SNT1035.

Other Refs: 41/15

<2> Haslam MJ, 1982, The Chilwell Story, 1915-1982: VC Factory and Ordnance Depot (Article in serial). SNT2622.

<3> Wayne D. Cocroft, 1997, RCHME: Dangerous Energy Project (Unpublished document). SNT6253.

<4> E. Wallace, 1919, The Real Shellman (Published document). SNT6254.

<5> Unknown, 1919, A short history of the National Shell Filling Factory Chilwell, Notts 1915-18 (Published document). SNT6255.

<6> David Lloyd George, 1933, War Memoirs (Volume II) (Published document). SNT6256.

<7> Public Record Office, 1915-18, Chilwell Photograph Albums (MUN5/154/1122.3/33) (Photograph). SNT6257.