Defence Evaluation and Research Agency

The Defence Evaluation and Research Agency (normally known as DERA) was a part of the UK Ministry of Defence (MoD) until July 2, 2001. At the time it was the United Kingdom's largest science and technology organisation. DERA was split into two organisations: short-lived transition bodies known as PDERA ("privatised" DERA) which became a commercial firm, QinetiQ, and "RDERA" (meaning "retained" in Government DERA) which became the Defence Science and Technology Laboratory (Dstl).

At the split, QinetiQ was formed from the majority (about 3/4 of the staff and most of the facilities) of DERA, with Dstl assuming responsibility for those aspects which were best done in government. A few examples of the work undertaken by Dstl include nuclear, chemical, and biological research. In the time since the split both organisations have undergone significant change programmes. QinetiQ has increased its focus on overseas research with a number of US and other foreign acquisitions, whereas Dstl has a major rationalisation programme aimed at changing many aspects of its operations.

DERA was formed in April 1995 as an amalgamation of the following organisations:
 * Defence Research Agency (DRA) which was set up in April 1991 and comprised the Royal Aerospace Establishment (RAE); Admiralty Research Establishment (ARE); Royal Armament Research and Development Establishment (RARDE); and, Royal Signals and Radar Establishment (RSRE)
 * Defence Test and Evaluation Organisation (DTEO)
 * Chemical and Biological Defence Establishment (CBDE at Porton Down), which became part of the Protection and Life Sciences Division (PLSD)
 * Centre for Defence Analysis (CDA).

The chief executive throughout DERA's existence was John Chisholm. DERA's staffing level was around 9000 scientists, technologists and support staff.