The Bomb Chamber (Building F16) and Detonation Chamber (Building F17) at Fort Halstead (Monument HOB UID 407330). In 1947 the High Explosives Research Headquarters was established at Fort Halstead and Britain's first atomic bomb the Blue Danube was developed here. Purpose built structures for this research were built in and around the fort, all within a secure fenced enclave. Fort Halstead was responsible for the development of both high explosive and electronic detonators for the atomic bomb. Britain's first atomic bomb was tested on the Mont Bello Islands, Australia on 3 October 1952. Atomic weapons research and development continued at Fort Halstead until 1955 when when staff transferred to the Atomic Weapons Research Establishment at Aldermaston in Berkshire.The Bomb Chamber, Building F16 was designed and built in July 1947. It is a reinforced rectangular concrete structure intended for the detonation of explosive devices with an E-shaped single armoured chamber. The Detonation Chamber (Building F17) was designed in August 1947 and is a bi-partite building of reinforced concrete and brick. The Bomb Chamber (Building F16) and Detonation Chamber (Building F17) at Fort Halstead are grade II* listed buildings. For the designation record of this site please see the National Heritage List for England.