Summary
The monument includes the standing, earthwork and buried remains of a Heavy Anti-aircraft (HAA) battery which dates from late 1938. After the Second World War it was part of the Nucleus Force until it was decommissioned in the 1950s.
Reasons for Designation
Portbury Heavy Anti-aircraft (HAA) Battery, which dates from late 1938 and remained in use until decommissioning in the 1950s, is scheduled for the following principal reasons:
* Survival: as a well-preserved and very legible example that retains its key structures. Portbury HAA battery is an important and evocative witness to national defence policy during both the Second World War and the Cold War, and to the significant role of ground-based anti-aircraft guns;
* Rarity: one of a small number nationally of complete or near-complete Second World War HAA gun sites that were adapted for continued service during the Cold War;
* Potential: the remains will enhance our detailed understanding of the form and operation of this type of military site in Britain.
History
During the late 1930s, with German rearmament progressing rapidly and the significant threat from aerial bombardment, close attention was given to Britain’s anti-aircraft defences. By the time war was declared in September 1939 Heavy Anti-aircraft (HAA) batteries had already been constructed at some of the country’s key locations. In all, almost 1000 were constructed nationally before the end of the Second world War. The standard weapons deployed at these sites were 3.7- and 4.5-inch calibre HAA guns with the function of engaging with high-flying strategic bombers, hence their location close to large cities, industrial and military targets, and around the south and east coasts. They were substantially built and, as well as the gun emplacements, which were usually in groups of either two, four or eight, they generally included operational buildings such as a command post, on-site magazines for storing reserve ammunition, gun stores and sometimes radar structures including a radar platform. Domestic sites were also a feature of HAA gun sites and comprised a variety of typical military buildings and hutting, such as barracks placed on concrete building platforms. The layout of HAA batteries was distinctive, but changed over time, for example to accommodate the introduction of radar from December 1940 and women soldiers from the Auxiliary Territorial Service (ATS) from summer 1941. After the war most anti-aircraft sites were abandoned, but 210 sites, known as the Nucleus Force, were retained to form the core of any future expansion of the country’s air defences. About half of them remained fully operational, while the rest were mothballed with guns stored off site.
The importance of the ports on the Bristol Channel led to the development of gun-defended areas at Bristol, Newport and Cardiff, and later Swansea. Portbury, also known as Bristol B2, was one of six HAA batteries established in late 1938 for the close defence of potential targets in the Bristol area. During the Second World War they were strengthened with a further 14 HAA batteries which increased the level of protection in the region, including for the city itself. Situated on the coastal plain to the east of Portishead and close to Sheepway village, Portbury gun site overlooks the Bristol Channel, and had a good line of sight to the docks at Portbury and Portishead and Portishead’s power station. Initially it was a mobile battery with sandbagged emplacements for 3.7-inch AA guns, but it had become a static site with four permanent emplacements focused on a central command post by July 1940. It was later modified for automatic gun laying using the 3.7-inch Mk II gun mounting, then re-armed with 4.5-inch guns in December 1942, and then in May 1944 with 3.7-inch Mark VI guns. Ground-laying (GL) Mark 1 radar was added, probably by late 1940, which enabled the guns to engage targets in poor visibility or at night. This was replaced during summer 1941 with a superior set. Portbury was first manned by 236 and 237 Battery of the 76th Heavy Anti-Aircraft Regiment but following the regiment’s deployment to North Africa from November 1942, it became a mixed battery employing female soldiers from the ATS. A Heinkel III H3 was hit by Portbury’s guns on 22 February 1941 causing the aircraft to lose altitude, hit a barrage balloon cable and crash into Portbury Wharf. One of the crew survived and was made a prisoner of war. This was a rare event since only two Luftwaffe aircraft are understood to have been brought down by Bristol’s gun sites throughout the war.
After the war, Portbury was selected for retention as part of the Cold War Nucleus Force, and operated as a Battery Headquarters, though the guns were not kept on site unless required. By spring 1955, anti-aircraft defence using artillery was declared obsolete and the last gun sites were decommissioned (Dobinson 1996 p231-9).
Portbury also had a domestic camp which contained the accommodation and related facilities not only for the personnel at the gun site but also for the crews deployed at barrage balloons and a bombing decoy nearby. It was described as well-appointed, with a NAAFI, interconnecting sleeping huts and indoor ablutions with hot water and flushing toilets. By 1960 almost all of the camp buildings had been demolished.
Details
PRINCIPAL ELEMENTS
The monument includes the standing, earthwork and buried remains of a Second World War Heavy Anti-Aircraft (HAA) battery located on the coastal plain overlooking the Bristol Channel. The gun site, known as Portbury or B2 (Bristol 2) in official records, was built in late 1938 as part of the first tranche of defences in the Bristol area. It was modified during the Second World War and in the Cold-War period was part of the Nucleus Force until it was decommissioned in the 1950s.
DESCRIPTION
During its period of use the battery was divided into two parts, the operational area which was originally surrounded by fencing, with a domestic site (not included in the scheduling) to the north and north-east, served by a concrete spine roadway running north to south with direct access from Wharf Lane. Just outside the gate to the field in which the gun site is located is a guard hut. It is a small brick structure with a flat concrete roof, with an open-fronted south-east elevation facing onto Wharf Lane. The three other elevations are blank, and part of the rear wall has collapsed. The camouflage paint scheme is a modern addition. The operational area, which formed the combat element of the site, included the gun emplacements, a command post, magazine, gun store and radar site. The four emplacements are arranged in an arc and linked by a semi-circular concrete road that comes off the spine road. Built to a general design first issued in 1938, each emplacement is octagonal and has a reinforced concrete blast wall that was previously embanked externally with earth for extra protection. There are wide opposing entrances (some infilled) in the wall, some of these retain hinges for blast doors. Set into the concrete floor is the central holdfast for the gun which had to be manoeuvred into place and a narrow duct that carried the cable to automatically fire the gun. There are six ammunition lockers, brick-built and mostly rendered, arranged against the inner face of the wall. Some of these retain armour-plated steel door surrounds. One locker (gun pit 2) has faint traces of painted silhouettes of aircraft, including a Heinkel bomber. Attached to the external face of the blast wall are two rectangular structures, one was for maintenance and for housing the hydraulic machinery and the other served as a rest shelter for the crew, though some were added later. None of the equipment, mechanisms or pipe work appears to survive. The emplacements were served by an ammunition store to the south-east which is accessed from a ramped concrete track to facilitate the movement of shells. This magazine follows a standard design produced by the Air Ministry in February 1939 and is a concrete, flat-roofed building protected within blast walls and an earth traverse. It is complete with three doors and two windows regularly spaced along its north side; the entrances providing access to the five internal bays, known as recesses.
At the rear (east) of the emplacements is the semi-sunken, concrete command post. It has two sections which are open to the sky and housed the identification telescope, height finder and predictor; three pieces of optical equipment for spotting and tracking enemy aircraft. Between the open parts is a flat-roofed building with two rooms. The largest room is interpreted as the plotting room where data from the height finder and predictor was converted into elevation, bearing and fuze timings for the guns. On the roof is a concrete stump, probably the pintle mounting for an anti-aircraft machine gun designed to engage low-flying aircraft trying to attack the gun site. The command post is built to a slightly amended form with the addition of a small brick and concrete structure for a central heating boiler to the rear, a standard modification on HAA gun sites employing female soldiers. The layout is complete, but there have been later alterations and, as is typical, it has been stripped of fittings. Immediately behind the command post are two air-raid shelters.
At the north-eastern end of the operational area is the gun store which was also used for gun maintenance and for storing tools and spare parts; it is now used for storage. It is a red brick, flat-roofed building with a widened front entrance and a pedestrian doorway in one of the side walls. It is likely there was an anti-aircraft machine gun on the roof. On the opposite side of the road to the gun store is where the radar platform was located. It is visible on aerial photographs from 1946 and 1947 as an enclosed semi-circular area with a central diamond pattern. It is no longer evident on the ground but associated buried features may survive. The aerial photographs also show several dispersed huts beyond the operational area which do not survive. Very little survives of the domestic camp which is not included in the scheduling.
EXTENT OF SCHEDULING
The monument includes the operational core of the site, namely the four gun emplacements, magazine, gun store, command post, radar site and sentry hut. The semi-circular road alongside the gun emplacements and a section of the spine road are also included. To the south-west and west the scheduling follows the line of a former boundary to the gun site which is shown on the 1968 Ordnance survey map. In the south-eastern part of the site the monument boundary includes the magazine and ramped tracks along with a 2m margin for their support and protection. It then runs alongside the roadway as far as the gun store before curving westwards on the north side of the northernmost gun emplacement.
EXCLUSIONS
The metal entrance gates and fenceposts are excluded from the scheduling, although the ground beneath these features is included.
