Royal Mail estimates there are over 100,000 post boxes in the United Kingdom. There are three types of post boxes: Pillar, Wall and Lamp.
Pillar Boxes are the most recognizable, cylinders, sunk into the ground with a round dome. Most traditional British pillar boxes produced after 1905 are made of cast iron and are cylindrical in shape. Other shapes have been used; the hexagonal Penfolds, rectangular boxes that have not proved to be popular, and an oval shape that is used mainly for the large double aperture boxes most often seen in large cities like London and Dublin.
Roadside wall boxes first appeared in 1857 as a cheaper alternative to pillar boxes, especially in rural districts; These first boxes were manufactured by Smith & Hawkes; Minor changes in design have been made over the years but essentially today’s wall boxes are little different to those of the 1930’s; In the 1950’s there was much complaint about the small posting apertures of the smaller wall boxes, as a result most of these boxes of Victoria, Edward V11 and George V were modified and received a wider slot.
Lamp Boxes are smaller and are fixed to posts or telegraph poles, usually in rural areas. Lamp Boxes were first used in 1897 based on the USA’s pattern and were intended to be used where there was not a convenient wall or where the volume of postings did not justify a wall box. By the 1960’s there were over 20,000 in use attached to lamp posts, telegraph poles or on their own free standing pedestal.
There are many variations of post boxes; one difference is the cipher on the front that identifies the reigning monarch. e.g. EIIR is Queen Elizabeth the Second.