The Joint Chemical, Biological, Radiological and Nuclear Regiment was a specialist expeditionary unit of the British armed forces. Personnel of the Joint CBRN Regiment were trained in the detection, identification and monitoring of nuclear, biological and chemical weapons. There were five regular squadrons; four from the 1st Royal Tank Regiment and one (No. 27 Squadron) from the RAF Regiment. Two squadrons (A and W) from the Royal Yeomanry and, from March 2004, 2623 Squadron RAF Regiment provided a reserve capability.