A pillbox is a type of blockhouse, or concrete dug-in guard post, normally equipped with loopholes through which to fire weapons. It is in effect a trench firing step hardened to protect against small-arms fire and grenades and raised to improve the field of fire.
A British World War II type 22 hexagonal pillbox in Kelling
on the North Norfolk coast, England. Pillbox broke up during winter storm February 2021.
A British World War II type 25 circular pillbox on Sheephatch Lane near Tilford
The origin of the term is disputed. It has been widely assumed to be a jocular reference to the perceived similarity of the fortifications to the cylindrical and hexagonal boxes in which medical pills were once sold; also, the first German concrete pillboxes discovered by the Allies in Belgium were so small and light that they were easily tilted or turned upside down by the nearby explosion of even medium (240mm) shells. However, it seems more likely that it originally alluded to pillar boxes, with a comparison being drawn between the loophole on the pillbox and the letter-slot on the pillar box.
The term is found in print in The Times on 2 August 1917, following the beginning of the Third Battle of Ypres; and in The Scotsman on 17 September 1917, following the German withdrawal onto the Hindenburg Line. Other unpublished occurrences have been found in war diaries and similar documents of about the same date; and in one instance, as "Pillar Box", as early as March 1916.
The concrete nature of pillboxes means that they are a feature of prepared positions. Some pillboxes were designed to be prefabricated and transported to their location for assembly. During World War I, Sir Ernest William Moir produced a design for concrete machine-gun pillboxes constructed from a system of interlocking precast concrete blocks, with a steel roof. Around 1500 Moir pillboxes were eventually produced (with blocks cast at Richborough in Kent) and sent to the Western Front in 1918.
Pillboxes are often camouflaged in order to conceal their location and to maximize the element of surprise. They may be part of a trench system, form an interlocking line of defence with other pillboxes by providing covering fire to each other (defence in depth), or they may be placed to guard strategic structures such as bridges and jetties.
Pillboxes were hard to defeat and required artillery, anti-tank weapons or grenades to overcome.
The French Maginot Line built between the world wars consisted of a massive bunker and tunnel complex, but as most of it was below ground little could be seen from the ground level. The exception were the concrete blockhouses, gun turrets, pillboxes and cupolas which were placed above ground to allow the garrison of the Maginot line to engage an attacking enemy.
Between the Abyssinian Crisis of 1936 and World War II, the British built about 200 pillboxes on the island of Malta for defence in case of an Italian invasion. Fewer than 100 pillboxes still exist, and most are found on the northeastern part of the island. A few of them have been restored and are cared for, but many others were demolished. Some pillboxes are still being destroyed nowadays as the authorities do not consider them to have any architectural or historic value, despite heritage NGOs calling to preserve them.
About 28,000 pillboxes and other hardened field fortifications were constructed in England in 1940 as part of the British anti-invasion preparations of World War II. About 6,500 of these structures still survive.
Pillboxes for the Czechoslovak border fortifications were built before World War II in Czechoslovakia in defence against a German attack. None of these were actually used against their intended enemy during the German invasion, but some were used against the advancing Soviet armies in 1945. The Japanese also made use of pillboxes in their fortifications of Iwo Jima.
- CBA staff, A Review Of The Defence of Britain Project, Council for British Archaeology, retrieved 30 May 2006
- Hellis, John (1 June 2001). "Why the name Pillbox?". Pillbox Study Group. Retrieved 10 September 2009.
- "pillbox, n.". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
- Oldham, Peter (2011). Pill Boxes on the Western Front: A Guide to the Design, Construction and Use of Concrete Pill Boxes, 1914–1918. Pen & Sword. ISBN 9781473817227.
- Oldham, Peter (2018). "'Pill box', 'pillbox' or 'pill-box'? What's in a name?". Stand To! The Journal of the Western Front Association. 112: 15–21.
- Schneider, Richard Harold; Kitchen, Ted (2002), Planning for crime prevention: a transatlantic perspective, RTPI library series, 3 (illustrated ed.), Routledge, p. 87, ISBN 978-0-415-24136-6