ROF Bridgend, (Filling Factory No. 2), located in Bridgend, South Wales, was one of the largest of sixteen World War II, UK government-owned, Royal Ordnance Factory munitions Filling Factories. Of great significance to the Britain's war effort, at its peak of production it employed around 40,000 people — said to be the largest ever factory in Britain's history.
At the end of World War I, much of Britain's armaments manufacturing capacity was run down, as its capacity was no longer needed. In the period leading up to World War II, consideration was given to Britain's war capability. As shown in the Spanish Civil War, the Luftwaffe were more than capable of accurately bombing many of Britain's key installations, which were also undersized to meet forecast required volumes.
In 1935, it was therefore agreed to keep armaments research at the Woolwich Arsenal in south-east London, while production would be transferred to two new factories at ROF Chorley in Lancashire (Filling Factory No.1) and ROF Bridgend in Glamorgan (Filling Factory No.2). As war planning progressed, it would be realised that this plan was flawed in both sustainability and capacity, and additional facilities would have to be built. Staff from the Royal Arsenal helped design and, in some cases, managed the construction of many of the new Royal Ordnance Factories (ROFs) and ROF Filling Factories. Just over 40 ROFs were opened by the end of World War II, nearly half of them Filling Factories, together with a similar number of factories built and run by private companies, such as ICI's Nobel Explosives (although these explosive factories were not called ROFs).
Bridgend was chosen for three main reasons:
In April 1936, 900 acres (3.6 km2) of land in Waterton was compulsorily purchased. The site chosen was farmland next to the Great Western Railway South Wales Main Line, which offered additional benefits. Located on what was a reclaimed marshland, a persistent local legend has it that the resultant dampness often resulted in the area being covered in a light mist or fog, which further protected it from bombing. Even if so, the drainage of the marshes caused the mist to cease. Further acreage was purchased in Brackla, leading to the development of ROF 11 and ROF 41.