Two Air Ministry J-Type Aircraft Sheds, or hangars, designed in 1939 by the Air Ministry Directorate of Works to design drawing 3084/39 and constructed by Sir William Arrol & Co. The western hangar was adapted in 1959 as the Receipt, Inspection and Maintenance (RIM) building for Thor missiles. The eastern hangar was converted into the Technical Storage building for the Thor project.

The two Air Ministry J-Type Aircraft Hangars, designed in 1939 by the Air Ministry Directorate of Works, are not listed for the following principal reasons:

Level of Architectural interest:

* no drawings of the modifications made to the western hangar for its adaptation as a RIM building have been discovered, and the uncertainty about the extent and nature of the alterations undergone by both hangars is compounded by the many subsequent uses to which they have been put; * the accumulative impact of multi-phase modifications on their fabric and layout is such that they simply do not survive in a form that illustrates and confirms their association with the Thor missile operation.

Level of Historic interest:

* the two J-Type hangars, particularly the western one which was adapted as the RIM building, had an extremely important role in the operation of the Thor missiles at North Luffenham, and they continue to provide architectural and historic context for the Grade II* listed missile emplacements, but they have undergone such extensive alterations that this role is no longer manifested in their physical form.

Construction of RAF North Luffenham was completed by late 1940. It was one of a series of stations established under the 1939 M Scheme for expanding the number of RAF airfields. Typically, airfields associated with this programme had two J-Type Aircraft Sheds, or hangars, flanking a Watch Office with a meteorological section of 1939 design, with associated technical buildings, domestic accommodation, and open grass flying field. The J-Type Aircraft Shed, or hangar, was a standard form designed in 1939 by the Air Ministry Directorate of Works to design drawing 3084/39 and were designed by Sir William Arrol and Co. They may be seen to bridge the hangar types built on the late 1920s and 1930s permanent airfields and later temporary wartime expedients. This type is typically associated with the maintenance of aircraft on operational airfields. Two hangars of this type were built at North Luffenham.

The station opened in January 1941 as Number 17 Elementary Flying Training School. By the summer of 1941, Numbers 61 and 144 Squadrons were brought to North Luffenham from Hemswell, but from 1943 work commenced to lay hard surfaced runways and hardstandings for heavy bombers. The airbase re-opened in March 1944 and was used initially by the Heavy Glider Conversion Unit, but returned to bomber crew training from September of that year until October 1945. Many airmen were lost from North Luffenham during the war, some within sight of the hangars. The base was bombed twice in the early part of the war. In December 1946 the Heavy Glider Conversion Unit returned to the airfield until December 1947 when the airfield passed to Transport Command and 240 Operational Conversion Unit. They stayed until April 1951 when Number 102 Flying Refresher School opened. With increasing East-West tensions in November 1951 it was decided that the airfield should be handed over to the Royal Canadian Air Force for the deployment of air defence fighters under the country’s obligations to the North Atlantic Treaty Organisation. The Canadians stayed until April 1955 when it passed to RAF Fighter Command before flying ceased in June 1958.

Around this time, the airfield was identified as a main base for a Thor intermediate range ballistic missile squadron, with four satellite stations at RAF Harrington, RAF Polebrook, RAF Melton Mowbray and RAF Folkingham. Thor missiles were the first operational Intermediate-Range Ballistic Missile (IRBM) system deployed by the West during the Cold War. The function of each main base was to receive the missiles and warheads from the United States and to inspect them after their journey before they were issued to a group of launch sites. Each main base had three launch emplacements, a Receipt, Inspection and Maintenance (RIM) building and a Technical Storage building. These buildings were adapted from existing RAF permanent build hangars. At North Luffenham, the western hangar was adapted as the Receipt, Inspection and Maintenance (RIM) building and work on its conversion was complete by October 1959. No drawings of the modifications made to this hangar to adapt it as a RIM building have been discovered. Probably at the time the hangar doors were permanently sealed and new openings created. The eastern J-Type Hangar was converted into the Technical Storage building for the Thor project. The modification was relatively minor in comparison to the RIM Building, involving the permanent closing of the original full-width sliding doors; provision of new, smaller openings; internal subdivision, improved lighting and heating and enhanced security. There was a ceremonial parade at North Luffenham to mark the (national) completion of Operation Emily on 5 May 1960.

Concurrently, a Tactical Control Centre with a Type 82 radar was in operation for the control of remotely based Bloodhound air defence missiles. The radar remained in service into the early 1970s as part of the civil air control system.

After the Thor missiles were stood down in August 1963 the airfield was used by a variety of RAF units. The western hangar was modified for use by the RAF Ground Radar Servicing Centre involving extensive subdivision of former open plan areas, construction of external hutting and changes to the ventilation and electrical installations. This use continued from November 1963 until November 1997. During this period major work involving the removal of asbestos took place in the Eastern hangar between November 1984 and July 1985. This involved emptying half the building in a phased manner for the work to be undertaken and then the other half for the second phase, effectively removing all traces of the earlier conversion of the building during the Cold War. Single-storey, timber constructed external hutting, very likely added for Thor operations, had been totally removed by 1997.

The RAF remained on the airfield until 1998 when it passed to the army and became known as St George’s Barracks. The western hangar remained empty until 2006 when it was occupied by the 16th Regiment Royal Artillery for Rapier maintenance, who continued there until 2014. There are drawings that show changes to the internal configuration required for Rapier maintenance. The 16th Regiment was replaced by the Royal Army Medical Corps who remained until 2018. The principal unit on the base in 2020 is the 1 Military Working Dogs Regiment, Royal Army Veterinary Corps. In November 2016 the Government published the document ‘A Better Defence Estate’ in which the closure of St George’s Barracks was announced.

Two Air Ministry J-Type Aircraft Sheds, or hangars, designed in 1939 by the Air Ministry Directorate of Works to design drawing 3084/39 and constructed by Sir William Arrol and Co. The western hangar was adapted in 1959 as the Receipt, Inspection and Maintenance (RIM) building for Thor missiles. The eastern hangar was converted into the Technical Storage building for the Thor project.

MATERIALS: the hangars are principally constructed from steel and brick with concrete floors.

PLAN: the hangars are located about 530m east of the main entrance on Edith Weston Road. They are rectangular in plan and are 300ft (91.44m) in length, 197ft 2in (60.09m) in width and to the roof apex measure 48ft 10ins (14.88m).

EXTERIOR: the J-Type hangars are 18 bays in length formed from arched steel lattice roof trusses supported by steel columns set at 16ft 8ins (5.08m) centres, giving a total length of 300ft (91.44m) and clear internal span of 150ft (45.72m). The ends of the roof trusses project outside the hangar and above the side annexes. The roofs are covered by 0.25 inch (0.635cm) mild steel plates. Typically, this hangar type had lifting tackle runways the width of the span, but here in both cases later inserted ceilings have obscured the roof structure. The hangars are entered at either end through 30ft (9.144m) tall steel-framed and steel-covered sliding doors mounted on rails. Each opening has six door leaves with steel end frames at either end to support the doors. Above the doors the span of the truss is sealed in corrugated iron.

To either side of the hangars are flat-roofed annexes that typically accommodated offices and crew rooms on the airfield side and workshops to the rear. These were lit by a large number of windows and entered from numerous doorways. All annexes show evidence of altered doorways, blocked windows, and all the window frames have been replaced. Above the annexes the main hangar walls are lit by a band of steel-framed windows and above these the wall was originally clad in corrugated iron. On the western end wall of the southern annex belonging to the western hangar is a faded painted plan of the airfield.

Probably as part of the conversion work to adapt the western hangar as the RIM building in 1959, the hangar doors were permanently sealed and new openings created. To the west a vehicle-sized opening was cut and a roller shutter door installed, a single smaller personnel entrance was also made. The eastern doors were also permanently closed and a roller shutter door inserted at the northern end giving access into a self-contained bay. Two smaller personnel doors and windows were also inserted into this hangar door.

INTERIOR: the internal alterations to the western hangar to adapt it as the RIM building in 1959 included the installation along the walls of a double row of flat plate radiators, the upper set angled downwards. The lower set has been removed and the position of the upper set obscured by a later suspended ceiling. In operation the missiles were brought into the west end of the building for inspection on their road trailers. Tests were carried out from a trailer mounted checkout station and a launching equipment simulator. The missile was also connected to a trailer mounted air conditioning unit. To manage the electrical supplies and other cabling sub-floor channels were laid, which remain visible in the floor with access covers by Elkington Gatic. Along the northern wall of the hangar brick compartmentalised workshops and offices were added, with a return that blocks access to the eastern hangar doors. In the centre of the hangar are two enclosed columns and a steel girder framework, whose tops are obscured by the suspended ceiling. These may represent extra supports for an overhead crane. At the eastern end of the hangar the roller shutter doors gave access to a self-contained bay. Within this area are two, free-standing, monorail overhead cranes with chain pulley blocks manufactured by Morris, each rated at 1 ton, running on pierced steel beams. Rooms were also set aside in the annexes for the squadron headquarters and missile control centre, which was permanently manned by an RAF missile controller and USAF authentication officer who had radio links to their respective headquarters.

When the RAF Regiment Rapier air defence unit was moved to North Luffenham in the 1970s, it is likely that the former RIM building retained a specialised maintenance function for the sensor systems of the Rapier missiles, which also required a controlled environment. During this phase it is likely that the suspended ceiling was inserted and associated lighting. Modifications were also probably made to the compartmentalised rooms to the north and east which are two-storey with upper offices. On the rear wall of the crane bay a clear horizontal break line is visible with a lower brick wall and an upper breeze block section. It is uncertain to which phase the cranes to the east belong. Currently this suite of rooms is used for offices and storage.

The eastern J-Type hangar was converted into the Technical Storage building for the Thor project. Its main hangar doors were also sealed and to the west a roller shutter door inserted for vehicle access and a single personnel door. To the east two vehicle-sized roller shutter doors and a single personnel door were installed. Internally, the hangar was divided lengthways into two sections by a steel framed and panelled wall with access between the two areas controlled by roller shutter doors. In the area to the south a free-standing brick-built compartment has been built. A suspended ceiling has also been inserted into this hangar and below this a piped fire suppression system covering the entire hangar.