National Filling Factory No.1 – Barnbow, Leeds

A site plan of National Filling Factory No.1 (Barnbow) after closure in 1924.

Facility Type & Function:

National Filling Factory (N.F.F.) – Filling of explosives into 13pdr, 18pdr and 4.5-inch, shrapnel and high explosive (HE) rounds, in addition to larger calibre Breech-loading (BL) shells and cartridges.

Brief History:

National Filling Factory No.1 Barnbow was the first purpose-built factory for filling Quick Firing (QF) shells and cartridges with explosives to be constructed under the National Factory Scheme.

Construction of this initially 296-acre site commenced in September 1915 by the contractor W. Irwin & Company Ltd. The factory officially opened in March 1916 with the first shells being filled in the following month.

It was predominantly engaged in the filling of 13pdr, 18pdr and 4.5-inch, shrapnel and high explosive (HE) rounds, although larger calibre Breech-loading (BL) shells and cartridges were also produced quantity.

By March of 1917, the factory employed 13,315 workers of which 12,150 were women. This was the highest percentage of women employed in any of the N.F.F.s. A third of the site’s workforce came from Leeds while the rest commuted daily in and out by train from as far away as York, Harrogate and Selby. The organisation of the factory staff was based on the novel principle of “dilution”. In this scheme, the tasks undertaken by single skilled worker, in pre-war times, were split into a series of simpler operations that could be performed repetitively by only semi-skilled workers. Training for the initial batch of factory workers was given at the shell filling sections of the Royal Ordnance Factory (Arsenal) at Woolwich.

A group of workers from National Filling Factory No.1 at Barnbow, Leeds (1916-18).

As in most explosives related factories, to reduce the risk of explosions, different stages in the shell filling and assembly process were carried out in different buildings, with the quantity of explosives in a building at any one time being limited. The buildings themselves were of light-weight timber-framed construction; those in the high risk “danger areas” of the works were designed to be “frangible”, i.e. to blow apart easily rather than concentrating the effects of blast in the event of an explosion occurring. To further prevent explosions in one area of the site propagating to neighbouring areas, many of the work huts and buildings were surrounded by earth bund walls which further help to direct any blast skywards.

The factory was served by an internal railway system with 13 miles of standard gauge lines connected to the national rail network. Materials were moved between, and sometimes through buildings, using horse-drawn tramways which constituted a further 10 miles of track. The site’s power supply was taken off a connection from the local Leeds area supply network.

By the end of the war, Barnbow had dispatched 566,000 tons of ammunition including 24,750,000 shells and 36,150,000 breech-loading cartridges of all sizes.

Barnbow Lasses” working in one of the several N.F.F. No.1’s shell packing sheds (1916-18).

As at other of the N.F.F.s, regrettably there were a number of accidents at the factory and explosions occurred on three separate occasions. The most serious incident occurred on the 5th December 1916, when 35 women were killed by a blast in one of the shell fusing rooms (Building 42). Although the explosion was heard for several miles, the deaths of the women and the treatment of the injured was not reported in the press. This incident was the first occasion that a large number of civilian women workers were killed while undertaking war work and it was feared that an announcement would have had a detrimental effect on morale and recruitment into similar factories.

Workers clearing the site of the remains of Hut 42 at the N.F.F. No.1 after the fatal explosion of 5th December 1916 which killed 35 “munitionettes”  and wounded many more.

Explosives (mainly cordite, and powdered TNT) were brought onto the site by rail and stored in magazines sited in the north-west factory until needed. Shell cases and other materials were brought into the eastern side of the factory and off-loaded to various storage sheds. Prior to filling with explosives (i.e. cordite, TNT or Amatol, which were prepared in a separate plant on the site) the empty shell casings were typically de-scaled and painted in rooms associated with the shell stores. The factory produced all its own timber packing cases. Workers arrived at a dedicated station, Barnbow Halt, which was situated to the south of the factory. On arrival at the site, all workers passed through a time recording office which had an adjacent security guardroom. Thereafter the workers passed through waiting rooms, then carrying on through the Women’s Canteen complex to the women’s or men’s Shift Changing Rooms. Here the workers changed into their magazine clothing (designed to prevent sparks) before proceeding onto the filling sheds via “cleanways” which comprised raised timber walkways. The filling sheds were arranged in long east-to-west blocks. Once filled and packed, the munitions were stored in earth bunded magazines operated by the Army Ordnance Department. These were located in the south-west part of the factory site.

Owing to the site breaking pre-war conventions by employing such a large female workforce, particular attention was given to the design and provision of welfare facilities on the site. The offices, canteens, general stores, and the shifting rooms were situated centrally, in the safest part of the factory complex. As in other similar facilities there were provisions for separate male and female canteens and shift changing rooms. Three canteens were provided, the largest accommodating 4000 workers, at two sittings of 45 minutes duration. The Amatol Plant canteen served 1000 at a sitting. Kitchens were equipped with the most up-to-date appliances including electric cookers, potato peelers, mincing machines, large pudding and potato steamers and vegetable boilers. A hot drinks buffet was available for people taking their own food. As at other similar National Factories there were dedicated on-site workwear laundries to service the works’ needs.

A group photograph of the staff of one of the Barnbow site canteens (1916-18).

The factory had its own dairy herd of 120 cows housed at Shippen House Farm to supply workers with milk, as this had been found to reduce the yellowing effect on skin caused by handling TNT. Vacant land was also cultivated to provide fresh produce for the canteens. In addition to the traditional pre-war explosives of cordite and TNT, the site also prepared Amatol. This was a newly developed explosive prepared by mixing ammonium nitrate with TNT. Barnbow’s Amatol Plant was constructed shortly after the main site had opened and was located in its own self-contained complex which included dedicated offices, canteens, shift changing rooms, stores, processing buildings plus railway loop. The layout of the new factory facilitated an efficient flow of materials throughout the filling process.

A part of a 1924 site plan of the Barnbow N.F.F. showing the details of the self contained Amatol Plant which was located in the south-east corner of the works.

Like many similar N.F.F.s, after the end of the Great War the sudden slump in demand for explosives brought about a rapid closure of the site. Instead of being totally dismantled and closed, the site and many of its buildings became Depot No. 85 Leeds as part of the Central Stores Department. It continued to be used immediately after the war for the de-commissioning of small arms ammunition and the storage and disposal of substantial volumes of surplus war materials. By 1924, the filling factory buildings had been largely demolished. In the same year Barnbow Colliery was sunk on the site of the former Amatol Plant. However, the pit was only short-lived closing in 1930. During the Second World War, and for a shortly afterwards, the site of the factory was used as a food store.

Extensive earthworks and building foundations from the original Filling Factory remain to be seen on the site to this day. As of 2016, the site has been scheduled and given National Heritage Status. A memorial and remembrance garden to all the “Barnbow Lasses” who were killed on the site during the Great War was also erected close to the former factory site in 2005.

Location Details:

Barnbow, Leeds, Yorkshire – National Factory Area No.3.

Associated Token, Check & Pass Issues:

Type I

Function: Canteen/Refreshment Token (Note 1).

Material: Brass

Design: Uniface with a plain edge and pierced for suspension

Shape & Size: Circular, 31.6 mm

Obverse: Incuse stamped legends around the outer upper and lower edges reads   AMATOL .F.F  (Note 2) and BARNBOW respectively and in centre field CANTEEN .

Reverse: Blank

Date: 1916 to 1918

Maker: Unknown

Published References: None but known to Malcolm Johnson (see Mal’s Tokens Web Site).


  1. There is a further possibility that this brass disc could represent a key identification fob used at the factory.
  2.  The initials F.F. represent the words Filling Factory.


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