Bulletproof and Shellproof Pillboxes of Square and Rectangular Shapes – Type 23
Although pillboxes in the group Type 23 follow similar guidelines, each individual pillbox is different. This diversity can be seen by differences in wall thickness, the amount of rifle loops, the materials used for construction, camouflage and other modifications such as shutters and blast walls. The construction of pillboxes required a casing to allow the concrete to be poured and dried in shape, this process is known as shuttering. When built the concrete may be shuttered with wooden boards, corrugated iron sheets or bricks. When shuttered with brick the shuttering was often left on the outside of the concrete casing, as it would have been inefficient to remove the mould. This added an extra layer to the pillboxes created in this way, often making them appear as made from bricks alone. It was realised that the pillboxes would be required to withstand artillery and dive-bomber attacks and so many pillboxes were made shellproof by increasing the thickness of the walls.
The Type 23 is a bulletproof or shellproof pillbox built in the shape of a square, often containing an open annex to allow room for a light anti-aircraft weapon. Loopholes are positioned in both the roofed and open area for a garrison of about four men. Entry to the Type 23 is usually via rungs set into the outer wall rather than a doorway. There are very few Type 23s left in Surrey, one is recorded on the Historic Environment Record near Ash Vale (See Historic Environment Record No.6389), and the Defence of Britain Project has recorded only 156 Type 23s left throughout Britain.
Surrey's pillboxes are included in the county's Historic Environment Record (HER), click the link to see more information.