History: World War II Photography, Anderson Shelter

Anderson shelters were designed to accommodate up to six people. The main principle of protection was based on curved and straight galvanised corrugated steel panels. Six curved panels were bolted together at the top, so forming the main body of the shelter, three straight sheets on either side, and two more straight panels were fixed to each end, one containing the door—a total of fourteen panels. A small drainage sump was often incorporated in the floor to collect rainwater seeping into the shelter. The shelters were 6 feet (1.8 m) high, 4.5 feet (1.4 m) wide, and 6.5 feet (2.0 m) long. They were buried 4 ft (1.2 m) deep in the soil and then covered with a minimum of 15 inches (38 cm) of soil above the roof. The earth banks could be planted with vegetables and flowers, that at times could be quite an appealing sight and in this way would become the subject of competitions of the best-planted shelter among householders in the neighbourhood. The internal fitting out of the shelter was left to the owner and so there were wide variations in comfort.
Anderson shelters were issued free to all householders who earned less than £5 a week (equivalent to £280 in 2015, when adjusted for inflation). Those with a higher income were charged £7 (£390 in 2015) for their shelter. One and a half million shelters of this type were distributed between February 1939 and the outbreak of war. During the war a further 2.1 million were erected. Large numbers were manufactured at John Summers & Sons ironworks at Shotton on Deeside with production peaking at 50,000 units per week.
The Anderson shelters performed well under blast and ground shock, because they had good connectivity and ductility, which meant that they could absorb a great deal of energy through plastic deformation without falling apart. (This was in marked contrast to other trench shelters which used concrete for the sides and roof, which were inherently unstable when disturbed by the effects of an explosion - if the roof slab lifted, the walls fell in under the static earth pressure; if the walls were pushed in, the roof would be unsupported at one edge and would fall.) However, when the pattern of all night alerts became established, it was realised that in winter Anderson shelters were cold damp holes in the ground and often flooded in wet weather, and so their occupancy factor would be poor. This led to the development of the indoor Morrison shelter.