In 2014, NAA carried out trial-trenching at a site in Howden, North Tyneside, in advance of construction of a block of sheltered housing. During the Second World War the site had been occupied by a heavy anti-aircraft battery, and contemporary aerial photographs indicated that one gun emplacement and an ancillary structure had been located within the development boundary. The two trenches were located to evaluate the degree of survival: Trench 1 was positioned over the gun emplacement, and Trench 2 over the other structure. Having demonstrated that substantial structural remains survived in Trench 1, and to a lesser extent in Trench 2, wider areas were excavated to record their full extent.

The site at Howden, designated Tyne L, was one of 29 heavy anti-aircraft batteries forming the Tyne Gun Defended Area during the Second World War, protecting the shipyards and ports which were essential to the war effort. The batteries were located away from built-up areas to give a good field of view and they operated in close collaboration with searchlight units. Batteries of eight guns were typically split between two sites, and initially the other half of the Howden battery (recorded in June 1940 as 176 Battery) was located across the Tyne at Lobley Hill in Gateshead. After the war, the Howden site was retained and eventually equipped with Bloodhound anti-aircraft missiles mounted on the same holdfast platforms to which the guns had been bolted, before finally being decommissioned by 1955.

At Howden, the four gun-pits were arranged around a central command post. To the north was a gun-laying radar. There would also have been magazines, maintenance and stores buildings, and accommodation for around 200 personnel which probably included women from the Auxiliary Territorial Service (ATS). Each gun-pit had an octagonal concrete pad with a steel holdfast mounted in the centre to hold the gun, and would have been protected by a concrete wall and steel gates. In the early part of the Second World War, the Howden site was equipped with pre-war 4.5-inch guns, although by 1945 these had been replaced with 3.7-inch Mark IIC guns. The later weapons, which were radar-guided, had remote power control, automatic fuse-setting and loading equipment, and each could fire 10 rounds a minute to a height of 41,000 feet (12,500m).

Despite extensive demolition in the 1950s, both archaeological excavation areas had substantial concrete remains. Trench 1 retained the octagonal reinforced concrete pad for the gun, which was 5m across and 0.4m thick. An unexpected feature was the pattern of eight radiating concrete arms each 0.5m wide and extending for between 2.4m and 3.8m. The arms had been constructed first, poured in situ, with the pad added in the centre. The main steel reinforcing bars within the arms were tied into a ring running within the central pad. The projecting outer ends had probably originally been similarly tied into a surrounding blast wall. The lower frame of the steel holdfast also survived. It was possible to record details of the arrangement of mounting bolts, and the course of the ducting for the power cable to remotely operate the gun was represented by a smooth area of concrete. Unusual survivals were two of the original wooden surveyor’s pegs used to lay out the site.

The remains in Trench 2 were less easily interpreted. A concrete pad measuring 3.5m by 2.6m was not reinforced but had a textured surface for grip, which suggests that it may have been an external feature, and aerial photographs from 1946 show it surrounded by a blast-bank. It may have been an emplacement for secondary armament such a Bofors cannon or Lewis machine-gun, intended to defend the site against low-level aerial attack.

Although other heavy anti-aircraft sites survive across Britain, they have not attracted much archaeological investigation; the only other excavation took place in advance of construction of the Olympic Park in London. As a result, the investigation at Howden was highly significant in recording previously unseen aspects of an emplacement structure. Although the central concrete holdfast was of standard type, it had only half the normal number of mounting bolts, suggesting that it had been re-used from an earlier site. The eight regularly spaced concrete arms have not been recorded anywhere else, and it has been suggested that they were added to avoid subsidence in a coal-mining area from the substantial and repeated recoil of the gun.