Former Heavy Anti-Aircraft gun site

Summary

Heavy Anti-Aircraft (HAA) gun site for 5.25 inch calibre guns, 1944, concrete.

Reasons for Designation

The former Heavy Anti-Aircraft gun site off Keelby Road, a Second World War HAA gun site for 5.25 inch guns, is designated at Grade II* for the following principal reasons:

* Rarity: One of only six surviving 5.25 inch HAA gun sites known nationally;
* Survival: For retaining the complete functional layout of the gun site including all four emplacements with their engine houses, the command post as well as the guardhouse/gunstore and the generator house;
* Technological: As an example of the most technologically advanced anti-aircraft gun site developed in the Second World War;
* Historical: As an illustration of the considerable investment made to counter bombing raids by the Luftwaffe;
* Social Interest: The design of the command post suggests that this was a gun site that employed female soldiers from the ATS, one of the milestones passed during the Second World War in the furtherance of equality between the sexes.

History

A HAA gun site was established at Little London, Stallingborough by June 1940 as part of the Second World War anti-aircraft defences centred around the Humber. This was known as Station S and was equipped with four 3.7 inch calibre guns set in concrete emplacements. In April 1944, construction was underway for four new, much larger and more complex emplacements for 5.25 inch calibre guns; the work being scheduled for completion in May 1944. This was designated as HAA gun site H20, and is known to have been one of just 15 gun sites nationally mounting 5.25 inch guns that were operational by 2nd November 1944 (Dobinson,1996 p103). After the end of the war, Stallingborough was one of those gun sites that was selected for retention as a Battery Headquarters (an armed, fully operational gun site) as part of the Nucleus Force documented in January 1946. It is not known when it was finally decommissioned, but it could well have been as late as spring 1955 when the use of artillery for anti-aircraft defence was finally abandoned and the last gun sites decommissioned (Dobinson, 1996 p231-9).

Part of the site was reused from 1961 when a Royal Observer Corps (ROC) nuclear fallout monitoring post was built and opened at the site. Some time between 1976 and 1984, the concrete emplacements and buildings associated with the 3.7 inch gun site were cleared. The site of this earlier HAA gun site was then returned to agricultural use.

A major feature of the Second World War was the strategic bombing of Britain by the German Luftwaffe. This prompted the construction of nearly 1000 HAA gun sites across the country, mostly using 4.5 and 3.7 inch calibre artillery and employed almost 275,000 men, in addition to women soldiers from the Auxiliary Territorial Service (ATS) from 1941 onwards. Unfortunately the German bombers could fly beyond the reach of these guns at heights of up to 40,000 feet. In October 1940 AA Command requested the allocation of 5.25 inch guns which could fire up to altitudes of 43,000 feet. These guns were substantially larger (84 tons) and more complex than existing HAA guns and were really intended for mounting on the decks of battleships. Emplacing them on land in an anti-aircraft role presented significant technical challenges. Three individual guns were emplaced around London by June 1942. An early design for the emplacements (DFW 55368) called for them to be sunken and constructed out of shuttered concrete, but these proved to take around 9 months to build and were prone to flooding. From July 1943 a new "accelerated construction" form of the emplacement was developed utilising concrete blockwork built up from the ground surface on a concrete raft. This led to the issuing of a new standard design in September 1944 (DFW 55487). In April 1944 18 sites across the country (each with four gun emplacements), were under construction with Stallingborough (along with three other sites on the Humber and two on the Thames/Medway) being the earliest expected to be completed in May 1944. It was originally planned to emplace 200 guns nationally, typically in four-gun batteries, and although construction continued after the war, it is thought that only 164 were finally deployed. Most anti-aircraft sites were abandoned after the war. This left only 210 sites nationally, known as the Nucleus Force, of which only about half were fully operational, the rest being mothballed with guns stored off site. By August 1946 about half of these 210 gun sites were decommissioned, generally retaining those with 5.25 inch guns. In 1950, a new scheme (codenamed Igloo) reduced the number to 78 sites, 54 being permanently armed. Heightened international tension caused by the Korean War (1950-53) led to the construction of a very small number of new 5.25 inch gun sites, but by spring 1955, anti-aircraft defence using artillery was declared obsolete and the last gun sites were decommissioned (Dobinson 1996 p231-9).

Details

PLAN: the operational core of the gun site was the command post which is shown on modern Ordnance Survey maps approximately 140m from the road. Forming an arc around the western side of the command post are the four gun emplacements, each with its attached engine house and the base of a crew rest shelter. Adjacent to the road is a linear range (the former guardhouse) and a taller square building (the former generator house).

COMMAND POST: this is a semi sunken, multi-roomed structure of concrete blockwork with a flat, reinforced concrete roof. It is built to a slightly modified form of the standard design (DFW 55402), the modification being the addition of a room to the rear for a central heating boiler, a standard modification on HAA gun sites employing female soldiers from the Auxiliary Territorial Service (ATS). The layout of the building is complete, but (as is typical) it has been almost entirely stripped of fittings. The open observation area on its southern side has been partially buried with later dumped material.

GUN EMPLACEMENTS: the emplacements follow the standard design DFW 55487 (the "accelerated construction" form of emplacement) built out of concrete block-work and rising from the surrounding land surface with a semi sunken engine room to one side, the emplacement and engine room being embanked with earth for blast protection. Each emplacement retains its circular metalwork holdfast set on a raised central drum. This is surrounded by a passageway into which spent cartridges were ejected and, in turn, encircled by a raised walkway where the gunnery crew operated the gun. The outer edge of this walkway is formed by ammunition lockers, which also acted as an outer blast wall to the emplacement. The attached, semi sunken engine room was designed to hold the hydraulic machinery which operated the gun. As is typical following de-commissioning, the emplacements have been stripped of equipment. Otherwise they are effectively complete and well preserved with one retaining the iron doors to the engine room. Outside each emplacement, just beyond a freestanding blast wall, there are also remains of a hut base, similar to, but smaller than, a standard Nissen hut. These huts are interpreted as being crew rest shelters.

GUARD HOUSE/GUN STORE: linear range of 7 bays (4 doors and 3 windows) with a flat reinforced concrete roof, retaining the original internal divisions. Converted into stables at the time of the inspection.

GENERATOR HOUSE: square building that is taller than the adjacent guard house. Retains louvered ventilation openings in the walls and ducts for cabling in the floor. Converted into stables at the time of the inspection.

SUBSIDIARY ITEMS: just west of the command post there are two small concrete structures which are interpreted as male and female latrines. The area between the emplacements and the command post is partially covered with rubble that is believed to be the demolished remains of the earlier 3.7 inch gun emplacements that were sited to the north. This area also retains inspection pits into the ducting that link the emplacements to the command post.

MAPPING NOTE: the gun emplacements are incorrectly mapped by the Ordnance Survey: omitting the staircases down to the engine rooms, the free standing blast walls, crew rest shelters and earthen embankments. One of the emplacements is also mapped with its engine room in the wrong position. The List Entry mapping is for indication purposes only and thus the gun emplacements, with their directly associated features, are indicated by circular areas. Similarly the small structures west of the command post (interpreted as male and female latrines) are not shown by the Ordnance Survey but are approximately identified by a small circular area.

Sources

Books and journals
Dobinson, C S, Twentieth Century Fortifications in England: Anti-aircraft artillery, 1914-46, (1996)
Lowry, B (ed), Twentieth Century defences in Britain. An introductory guide, (1995)

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