Building Q14, Fort Halstead

Building Q14 at Fort Halstead is a former purpose-built assembly building for the atomic bomb prototype warhead, constructed in the late 1940s with late 20th-century and early 21st-century modifications.

Construction and Materials

The building is constructed of red brick in stretcher bond encasing a presumed steel frame, with a concrete roof.

Layout

This is a rectangular two-storey building with a flat roof, oriented north-south. The ground floor comprises a double-height workshop, whilst the first floor is reached by a staircase at the south end.

Exterior

The ground floor is double-height throughout. The main entrance is in the south elevation through glazed double doors. A further pedestrian entrance to the east is now blocked, and there is another at the north-east corner of the building. A blocked large equipment entrance to the south-west retains its original exterior wall light. The door head suggests a former roller shutter door, now partly obscured by a later plant room (which is not of special interest).

The east elevation, which was public-facing at the edge of the High Explosives Research compound until 1952 when the boundary moved eastwards, was originally blind at ground floor level, presumably to conceal the highly secretive nature of the work taking place inside. The current ground floor windows are therefore secondary insertions. The original fenestration form to the west and north elevations remains legible as double-height windows to the ground floor which lit the workshop inside. These large openings are now bricked up with smaller ground floor windows inserted. All first floor windows are uPVC replacements, although they reuse the original window openings. A fire escape is present on the north elevation. (The replacement uPVC windows and fire escape are not of special interest.)

On the west elevation, a memorial plaque bearing the crest of the Royal Armament Research and Development Establishment reads: "In this building a group of scientists & engineers led by the then Dr W G Penney worked on United Kingdom atomic warheads during the period 1946 to 1952. This plaque was unveiled on 6th April 1982 by Lord Penney OM. KBE. MA. PhD. D Sc. FRS."

Interior

The interior was not inspected but the ground floor was viewed through windows. With the exception of the south entrance area and staircase, the ground floor comprises a single double-height workshop space which has a later inserted ceiling. An English Heritage internal inspection in May 2008 confirmed steel framing in the ceiling void of the workshop area, although it was not possible to establish whether this was structural or a gantry for the travelling crane which is known to have been here originally. The staircase appears slightly modified with replacement modern treads. The Waterman gazetteer of 2009 confirms that the first floor has a spine corridor providing access to office space.

Historical Background

Fort Halstead is a late 19th-century mobilisation centre, one of a ring of thirteen similar sites interspersed with entrenchments which were constructed to protect London in the 1890s against any potential invading force. These mobilisation centres were intended to be nodal points where a volunteer force could collect equipment and ammunition and defend the capital in the event of invasion. The capital was not encircled by these centres but was protected to its north-east, east and south—the anticipated directions of attack—and their construction represents a lack of confidence in the Royal Navy's ability to protect the country from its enemies at that time. Plans for Fort Halstead were drawn up by 1894 and it was probably constructed between 1895 and 1897. During the First World War the fort continued to be used as a defendable ammunition store, forming part of a London stop-line (an anti-invasion defensive line) with a laboratory (possibly for the inspection of ammunition) built there in 1914 (building F14). In 1921 it was sold to a private individual.

In 1937 Fort Halstead was repurchased by the War Office in order to provide accommodation for the Projectile Development Establishment (established here in 1938 under the directorship of Alwyn Crow) as it provided a remote and contained site for rocket development. Interest in rocketry had revived in 1936 with initial work taking place in the Ballistics Branch at the Royal Arsenal in Woolwich under Dr H J Poole. However, Woolwich was soon considered an inappropriate location given safety concerns, not least the proximity of dense populations: Fort Halstead was preferable in this respect. One experimental filling shed (building F11) is the earliest surviving building in England to be associated with rocketry. It is from the late 1930s that the Fort Halstead site began to expand with a number of buildings constructed both inside and outside of the fort, including some of those under assessment here. In 1940 the Armament Research and Armament Design departments took up residence at Halstead Place nearby.

At the end of the war, research continued although in a scaled-down form, but in January 1947 the British cabinet took the decision to proceed with the development of an atomic bomb. In May of the same year this task was entrusted to William Penney, Chief Superintendent of Armaments Research at Fort Halstead. Penney was a physicist and had been a leading member of the wartime British Mission to the United States Manhattan Project which had been responsible for creating the first atomic bombs. He played a prominent role in the project, and in addition to his scientific contributions also sat on the Target Committee, which discussed which Japanese cities should be attacked, and flew with the mission that dropped the bomb on Nagasaki to film its results. Fort Halstead thus became the headquarters of High Explosives Research, a top secret research branch whose name also hid the true focus of its work which was to develop Britain's first atomic bomb. Many purpose-built structures were erected both inside and outside the fort including electronics, engineering, mathematics and theoretical physics departments provided with drawing offices, laboratories and test stands, all within a secure fenced enclave. By the end of 1950, the atomic bomb project (developing the Mark 1 warhead which when assembled in its casing for service was known as 'Blue Danube') dominated work at Fort Halstead with nearly two thirds of the approximately 1,000 posts allocated to High Explosives Research. The link between this project and the fort was a closely guarded secret. Even within government all orders were routed through the largely civil Atomic Energy Research Establishment Harwell, Oxfordshire, until 1949.

In common with other government research establishments involved with weaponry research and development there is very little in the public domain in the way of documentary evidence to aid our understanding of the details of the programme development here. What is clear is that the Fort Halstead personnel were responsible for developing the ball of conventional high explosives and associated detonators which would produce an implosion to trigger the plutonium core and create a nuclear explosion. In particular, they developed the electronic detonators which had to work simultaneously to detonate the bomb's 32 explosive lenses. As always with development programmes of this era different and often distant sites were responsible for research, development, manufacture and testing of the different component parts of weapons systems. The Royal Arsenal, Woolwich (London) was responsible for the main conventional explosives work with test assembly and firing at the AWRE Foulness range (Essex) where work on the live explosive lenses also took place. The ballistic casing was developed at the Royal Aircraft Establishment in Farnborough (Hampshire). The casings were mostly manufactured by Hudswell Clarke and Co Ltd, Leeds (Yorkshire). Percival Aircraft, Luton were involved with the design of the sphere that contained the high explosive and fissile components. Internal electrical components were made both at High Explosives Research's Woolwich Common factory and by private companies. Ballistic trials took place at the Orford Ness range (Suffolk) in the late 1940s and early 1950s, dropped by the RAF, with further assembly of inert trial rounds at the nearby RAF Woodbridge.

From inception there was very close co-operation between High Explosives Research and the RAF with Squadron Leader John Rowlands heading the RAF team of ten involved with the atomic bomb's development. His role was to understand the science and engineering and thus guide the RAF in its future storage, maintenance and operation of the bomb and, of course, to ensure that it was developed to the satisfaction of the Air Ministry. Rowlands, with Squadron Leaders Brown, Mitchell and Skelley and Flight Lieutenant Blythe were responsible for the weapon's assembly. Squadron Leaders Betts and Pulvermacher worked on the electronics, Flight Lieutenant Mercer on explosives, Wing Commander Hunter-Toddy joined the mathematics team and there was also a general duties officer.

In terms of the Fort Halstead High Explosives Research personnel, Leonard Tyte was in charge of electronics and high speed measurements with John Challens leading the electronics team, assisted by Bernard Hillam and Edward House, and Ieuan Maddock had responsibility for high speed measurements and testing the detonators. Klaus Fuchs was also a contributor in the early years of work at Fort Halstead although he was based at AERE Harwell (Oxfordshire). An émigré German scientist, he had previously worked on the US Manhattan Project so came to Fort Halstead to share his knowledge of that programme. However, he was subsequently discovered to be a Soviet spy. For both safety and secrecy, some of the atomic bomb work took place within the fort.

Britain exploded her first atomic bomb on the Mont Bello Islands, Australia on 3 October 1952, known as the 'Hurricane' trial. Rowlands and Mitchell from the RAF team transported the radioactive components from the UK and with William Moyce from the High Explosives Research team assembled the test device which successfully detonated. The following year Rowlands took command of RAF Wittering's Bomber Command Armament School, the first recipients of atomic weapons. Bomb stores at RAF Wittering associated with this deployment are currently under assessment for listing.

Atomic weapons research and development continued at Fort Halstead until 1955 when staff were transferred to a new Atomic Weapons Research Establishment at Aldermaston in Berkshire. Since the mid-1950s Fort Halstead has continued to operate as a government defence research establishment but concentrating on explosives and other research.

No design drawings have been located for Q14 and it is not shown on aerial photographs of April 1947, indicating that it was built subsequently, but is visible on photographs of May 1952. The dates on the memorial plaque on the west wall are curious, as work could not have taken place in this building as early as 1946 as it had not been built at that date and indeed Penney was not appointed until May 1947, yet he unveiled the plaque.

Q14 was a purpose-built structure designed for the assembly of the prototype warhead and its ballistic casing: it was central to Rowland's task to ensure that all the component parts fitted together in the casing. It was the only place where all the component parts of the bomb were brought together and where a complete model was assembled, although inert model wooden replicas were used instead of the live explosive components. (The colloquial name for Q14 was the 'RAF Building', illustrating the close collaboration between Penney's team and the end user, the RAF.) It is not known where the electronic components of the trial devices, which were then taken to RAF Woodbridge (Suffolk) were assembled although Q14 is a possibility.

Building Q14 is listed for its considerable national significance through its association with William Penney, Chief Superintendent of Armaments Research, who led Britain's atomic bomb development programme here and which association is celebrated by a memorial plaque. It is the only building nationally where the prototype bomb was put together and was thus instrumental in the detonation of Britain's first atomic bomb in 1952. Although a functional building without architectural embellishment its form expresses the secrecy surrounding the programme, being blind on the public-facing side, and it retains its original workshop space and support accommodation for the assembly of the prototype warhead and ballistic casing. It also has group value for its associations with Fort Halstead and the contemporary buildings within and outside of the mobilisation centre which were also part of the atomic bomb development work.