Bofors tower approximately 500 metres north north west of Christ Church

Bofors gun tower, approximately 500 metres north north west of Christ Church, Dunkirk. 1940. Reinforced concrete and brick.

The structure stands to a height of about 5 metres and consists of two parallel, independent towers separated for much of their height by a 1.2 metre wide gap. At ground level this gap functioned as a passageway, providing access to the chambers on either side. The passage opens onto a level walkway surrounding the base of the two towers and partly sunk into the crest of the hill to the east.

The larger, southern tower measures about 10 metres east to west by 7 metres north to south and was constructed on two levels comprising two brick-walled ground floor chambers with the ordnance emplacement on the roof. The open roof space is reached from ground level via external concrete steps attached to the southern side of the tower. The Bofors gun, which had an effective range of about 2 kilometres, was mounted at the centre of the roof on a low hexagonal concrete drum. This still survives together with its steel holdfast frame. The gun position is flanked by two ammunition lockers set behind the parapet to the east and west. The western cell is cantilevered out beyond the wall of the tower below and is supported by three concrete piers. The eastern cell has been under-built in brick creating a second chamber at ground level.

The adjacent tower measures about 5 square metres and supported the target predictor on its flat concrete roof. The intervening gap insulated this sensitive equipment from the vibration of the Bofors gun. Photographic evidence of a similar tower during operation suggests that the much lighter Lewis gun may have been placed at the centre of this roof, with the predictor installed alongside. This roof platform is raised slightly above the level of the adjacent tower and is cantilevered across the intervening passage without touching the main gun tower platform. It can be reached directly from the Bofors platform via a step set into the edge of the position, or by way of external concrete steps on its northern side. These steps also provide access to the chamber below, which housed an ammunition store linked to the Bofors gun platform by two openings situated at the top of its southern wall.

The concrete and brick built gun tower conforms to type DFW 55087, which was designed at the end of 1939 with the earliest examples constructed during the first half of 1940. The tower was designed to raise a 40 millimetre Bofors gun and its operational equipment above surrounding obstacles in order to achieve an all-round field of fire. At Dunkirk the Bofors tower was partly concealed in an area of light woodland to defend the radar station from attack by fast moving, low flying enemy aircraft. A Lewis gun provided the ground defence of this position.

By June 1939 Dunkirk radar station was identified by the War Office as one of five sites in England most vulnerable to attack and was allocated the designation Vulnerable Point (VP) 126. In common with other Vulnerable Points, Dunkirk subsequently became a strongly fortified position. From as early as September 1939 the site's anti-aircraft provision included three 40 millimetre Bofors and eight Lewis guns. Fears of German paratroop raids led to the construction of additional perimeter defences, including four infantry pillboxes and Lewis guns for ground defence. By July 1940 the number of Lewis guns had been temporarily increased to 18. The defences were further strengthened by the addition of the tower-mounted Bofors gun and a quad Vickers machine gun, both of which were in place by the end of January 1942.

This World War II Bofors anti-aircraft gun tower is one of the few remaining examples of its type in the country. The importance of radar stations in providing long range early warning was fully recognised during World War II and a high priority was given to their defence. The substantially built Bofors tower at Dunkirk is a graphic indication of the necessity to safeguard the radar installation, one of the crucial elements in the strategic defence of Britain against the threat of invasion during the principal conflict of the twentieth century.