Monument record LCS 106 - World War II strongpoints and a Light and Heavy Anti-aircraft Artillery site.

A group of early World War II barbed wire emplacements, or strongpoints, and a Heavy Anti-aircraft Artillery site with a possible paired Light Anti-aircraft machine gun site, are visible on aerial photographs as structures and earthworks at Sizewell in Leiston parish, roughly centred on TM64376371. In 1940 photographs three well defined strongpoints are visible, defined by barbed wire obstructions surrounding pillboxes and trenches. They are centred on circa TM47336353, TM47136367 and TM47296383. In 1940 The first of the three, at TM47336353 is located upon a slight bank (see LCS 107), and is actually formed of two 'cells' of barbed wire; a circular strongpoint with a semi-circular annexe to the west. Each has a pillbox, slit trenches and weapons pits in its centre. The main cell is just under 1 hectare in area, and the annexe is circa 0.7 hectares. These appear to be located to control the access road to the coast which bisects the enclosures. The other two strongpoints have their foci at TM47136367 and TM47296383. The latter is centred on an enclosure of just over 1 hectare, but contains a substantial length of trench, over 200m in length, connecting at least three pillboxes, which extends into a substanstial barbed wire annexe to the west of circa 0.9 hectares. This annexe abuts the third strongpoint at TM47136367, which is circa 1.2 hectares in area. This is again formed of two cells, the main one being just over 1 hectare, and a second smaller cell adjoining it to the north, of circa 0.2 hectares. It is not clear from the photographs what form the structure takes in the centre of this strongpoint, and it may have been under development or demolition by 1940. By 1941, the two larger strongpoints at TM47336353 and TM47296383 join to form one larger emplacement of circa 7 hectares, with additional structures and earthwork fieldworks located at circa TM47256381 and TM47196376. The smaller strongpoint to the west has probably gone out of use by this time, but the photographs available do not extend very far west and we therefore cannot be certain of the military activity in this area at this time. The next available photographs for this area are from October 1945. By this time, all of the strongpoints have been superseded by a Heavy Anti-aircraft Artillery site and its associated camp, centred on circa TM47396362. This site appears to be part of the DIVER strip, installed between June and November 1944 to combat the V1 'flying bomb'. By October 1945, all of the guns and the camps Nissen huts have been removed, and their locations are visible only from their concrete foundations. In addition to the four heavy gun posts located in a straight line from TM47396362 to 47326370, the 1945 photographs show two areas of activity which apear to be smaller scale lines of gun posts, centred on circa TM47276360 and TM47246372. These may be earlier, more temporary DIVER emplacements, or associated Light Anti-aircraft machine gun emplacements. Traces of the DIVER site, and a number of the pillboxes and trenches are visible on aerial photography of 1958, but are destroyed by 1968 and the construction of Sizewell powers station. (S1-S5).