Royal Ordnance Factory

Royal Ordnance Factories (ROFs) were munitions factories run by the UK government during and after the Second World War. The three main types of factories were engineering, filling and explosives, and these were dispersed across the country for security reasons. ROFs were the responsibility of the Ministry of Supply and later the Ministry of Defence until privatisation in 1987.

Prior to the 1930s, Britain's ordnance manufacturing capability had been concentrated within the Royal Arsenal, Woolwich. In the late nineteenth century, the term 'Royal Ordnance Factories' began to be used collectively of the manufacturing departments of the Arsenal, principally the Royal Laboratory, Royal Gun Factory and Royal Carriage Works, which, though they shared the same site, operated independently of one another. This use of the term is seen in the name of the 1893 Royal Ordnance Factories Football Club and it continued through the First World War. The emerging threat of aerial bombing prompted the government to consider dispersing its ordnance factories around the country.

The majority of the ROFs were built during the re-armament period, just before the start of the Second World War, to enhance the capacity of the three ordnance sites that had continued in operation after the end of the First World War: the Royal Arsenal, Woolwich, the Royal Gunpowder Factory (RGPF) Waltham Abbey, Essex and the Royal Small Arms Factory, (RSAF) Enfield. These three sites were in or near London and were considered to be vulnerable to aerial bombing from continental Europe.

The Royal Arsenal designed many of the ROFs and was also the agent for the construction of all of the Rifles ROFs, the Medium Machine ROF and the Small Arms Ammunition ROFs. The Ministry of Supply, the Ministry of Works, and two other private companies were agents for the construction of the remaining ROFs.

A number of Second World War munitions factories were built, and owned, by Imperial Chemical Industries (ICI). These ICI Nobel Explosives owned factories were not considered part of the Ministry of Supply's Royal Ordnance Factory organization, and they were not called ROFs. ICI also managed munitions factories constructed with Ministry of Supply funding. These were known as "agency factories" and three of them became part of Royal Ordnance upon the ROFs' privatisation.

Some of the ROF filling factories built later, during the Second World War, were government-owned, but managed, as agency factories, by private companies unconnected with the explosives industry. For example, Joseph Lyons & Co ran ROF Elstow throughout the war. Other filling factories were run by Imperial Tobacco, Courtaulds, the Co-operative Wholesale Society (CWS), Metal Closures and Lever Brothers.

The new ROFs were to be built in areas regarded as "relatively safe". Until 1940, this meant from Bristol, in the south, and then west of a line that ran from (roughly) Weston-super-Mare, in Somerset, northwards to Haltwhistle, Northumberland; and then northwestwards to Linlithgow, in Scotland. The South, South East and East of England were regarded as "dangerous" and the Midlands area, including Birmingham as "unsafe". This definition of "safe" area was later changed, and in 1940 ignored in the case of ROF Chorley.

Siting of the individual ROFs north and west of this line was of vital importance. ROFs involved with explosive manufacture or filling needed, on safety grounds, to be located away from centres of population. They needed access to good transport links, such as railways, the availability of adequate workers within reasonable travelling distance, and a plentiful guaranteed supply of clean process water. To avoid the danger of frozen explosives, they tended to be located at or just above sea level. Some ROFs located in Wales and Scotland were the result of political lobbying as these areas had high unemployment rates in the 1930s. The ROFs were guarded by what was to become the Ministry of Defence Police.