On 22 April 1915, on a First World War battlefield in France, the German Army first deployed chemical warfare (CW). The British responded in kind five months later, on 25 September 1915.
The following year, land at Porton Down was acquired as the War Department experimental ground for CW trials. Later in 1916 the site became the Royal Engineers Experimental Station and this title persisted until 1929 when the facility became in turn: Chemical Warfare Experimental Station (CWES) 1929-1930; Chemical Defence Experimental Station (CDES) 1930-1948; Chemical Defence Experimental Establishment (CDEE) 1948-1970; Chemical Defence Establishment (CDE) 1970-1991; Chemical and Biological Defence Establishment (CBDE) 1991-1995.
CBDE was amalgamated into the Defence Evaluation and Research Agency (DERA) on 1 April 1995. However, the 1998 Strategic Defence Review resulted in DERA being split into two organisations, one to remain within MOD but the other to become a UK plc, in July 2001. CBDE was placed within the Defence Science and Technology Laboratory (Dstl), the organisation retained by MOD.
Whilst Porton Down was originally controlled by the War Office, it has always been tri-service in its composition. The facility passed to the Ministry of Supply (MOS) in 1939 and remained under MOS control until 1959 when it came under the aegis of the War Department (WD), passing again to the new Ministry of Defence (MOD) in 1964. In the years following the Second World War, Porton Down was guided by the Chemical Defence Advisory Board (CDAB) under the aegis of the MOS Advisory Council on Scientific Research and Technical Development (generally known as the Scientific Advisory Council (SAC). By 1969 the Council was formally termed the MOS Defence Scientific Advisory Council. (DSAC). The Board, dropping"Advisory" from its title, became CDB in 1982.
The original purpose of the facility had been field trials with CW, but the end of the First World War saw the role of the Porton Down facility expanding to include applied research in meteorology, medicine, physiology, chemistry, physics and engineering, and to encompass both offence and defence. The role of Porton Down became solely defensive in 1956, when the UK abandoned its offensive CW capability.
An outstation, later to become the Chemical Defence Research Establishment (CDRE), was established at Sutton Oak (in St Helens, Lancashire) in the early 1920's. CDRE's role was technical research for the ultimate transfer of laboratory sales of CW agent production to the chemical industry for full-scale production. CDRE closed in 1954 and its role was transferred to the Chemical Defence Establishment at Nancekuke, Cornwall. In 1962 this establishment became a Division of the Porton Down facility, which had by that time become the CDEE. The Nancekuke Division closed in 1980.
The Second World War saw an upsurge of activity at Porton Down and for decades afterwards much effort was devoted to nerve agents, first developed in Germany. Later there was considerable work on riot control agents in response to the troubles in Northern Ireland.
In 1940 biological warfare (BW) work began at Porton, in a highly secret autonomous group called Biology Department, Porton (BDP), located initially within CDES. BDP became the Microbiological Research Department (MRD) in 1946 and moved into its own, new buildings, constructed on adjacent land in 1948-1951. It was re-named the Microbiological Research Establishment (MRE) in 1957. MRD and MRE were guided under the aegis of SAC and DSAC by the Biological Research Advisory Board (BRAB) until 1977 when the CDB became the Chemical and Biological Defence Board (CBDB). In 1979 MRE closed and responsibility for BW research passed to the Chemical Defence Establishment (CDE), although this new role did not feature in the establishment's title until 1991, when CDE was finally re-named the Chemical and Biological Defence Establishment (CBDE).
The MRE building meanwhile became the Centre for Applied Microbiology and Research (CAMR) within the Public Health Laboratory Service (PHLS) and thus under the Department of Health.