World War II Heavy Anti-Aircraft (Haa) Battery

Slade's Green World War II Heavy Anti-Aircraft (HAA) Battery

This is a well-preserved Heavy Anti-aircraft battery of late 1930s construction, located off Wallhouse Road near Slade's Green. The site comprises four gun emplacements, a command post, two defensive pillboxes, an air raid shelter, and a Bofors gun emplacement. All structures are built of reinforced concrete and brick.

The battery is laid out with a command post at its centre, around which four gun emplacements for 4.5 inch guns are arranged in an arc running northwest to southeast. Two Type 24 hexagonal pillboxes defend the site to the northwest and southeast, with an air raid shelter positioned to the southeast. To the northeast are the overgrown remains of a Bofors gun emplacement. Fragmentary remains of support buildings and domestic structures survive to the southwest of the command post as foundations and concrete platforms, but these are not formally listed due to their poor state of preservation.

The four gun emplacements are octagonal enclosures approximately 13 metres in diameter, each with opposing entrances about 4 metres wide. Each contains six flat-roofed lockers measuring 2 metres long, 1.8 metres wide and 1.6 metres high, with cavity walls, air vents and rubber seals to metal door frames (though doors are missing). The northwest emplacement retains its original central holdfast for the gun, approximately 4 metres in diameter with surviving fittings—this is the clearest example on the site. All emplacements show evidence of drainage, camouflage fixings on the enclosure walls and external earth banks. The northeast emplacement has north-south entrances; the east emplacement has west-east entrances with remnants of solid wooden plank gates and sandbags protecting one gateway pier; the southeast emplacement has northwest-southeast entrances and is notable for retaining a metal sight mounted between a pair of lockers.

The command post is an irregular semi-sunken structure with flat roofs to the north and open courtyard zones to the south, oriented northwest to southeast with a northeast extension possibly for light anti-aircraft guns or radar. External fixtures include camouflage fixings, a triangular roof mount and a metal plotting table. Access is via entrances to the southwest with steps down. Though flooded at inspection, the interior plan and divisions appear largely intact.

The northern and southern pillboxes are both Type 24 structures of stock brick and reinforced concrete. Each has a concrete porch protecting a low entrance (southeast for the northern pillbox, northwest for the southern), with patching above suggesting later modifications. Both have concrete cills to their embrasures and internally retain straight ricochet walls.

The air raid shelter is broadly rectangular with flat roof and two projecting porches to the south protecting corner entrances. Built of brick and reinforced concrete, it features two unusual diamond-shaped openings in the north elevation with brick header surrounds. These light two north-south entrance corridors internally, which provide access to two parallel west-east rooms.

The Bofors gun emplacement is now heavily overgrown but aerial photographic evidence indicates a polygonal concrete enclosure with central gun holdfast.

Slade's Green Battery was one of several Heavy Anti-aircraft batteries positioned to create a protective ring around London during the Second World War. Allocated the site code ZS1 as part of the London Inner Artillery Zone, it was the most easterly battery in that zone. Its position just south of the River Thames on the Crayford Marshes placed it strategically to engage enemy bombers attacking London from the east and to protect local military targets such as the Vickers-Armstrong factory in Crayford. The site was first documented on 22 January 1940, though its layout indicates late 1930s origin. Records show it was manned in January and May 1940 by the 54th Regiment (160 Battery) and in July 1942 by the 164th Regiment (446 Battery). Originally protected by two pillboxes, a Bofors gun emplacement was added later in the war.

The battery exemplifies the substantial nature of Heavy Anti-aircraft batteries, which were the largest Second World War anti-aircraft sites and housed guns of 3.7, 4.5 or 5.25 inch calibres. Gun emplacements were typically arranged in groups of four or eight, and batteries incorporated command posts, radar facilities, ammunition magazines, gun stores, power generation huts and domestic structures. Close defence was provided through pillboxes and other fortifications. During the war, Anti-aircraft Command reached a peak strength of 274,900 men, supplemented by women soldiers of the Auxiliary Territorial Service from summer 1941 and the Home Guard later in the conflict.