Besides the original green boxes – now only to be seen in museums – there was a period where blue post boxes were briefly in vogue. These boxes, such as this George V example, which stands outside Windsor Castle, were for air mail. They were introduced to tourist venues between 1930 and 1938. However, having separate air mail boxes proved to be too costly and in 1938 the Royal Mail decided that the public could use any box to post air letters. The Windsor box is now a tourist attraction only
The first pillar box was introduced to the British Isles on this day in 1852. This model post box was made to stand in the entrance hall of a large country house. A servant would empty the box each day and take the letters to the nearest post office. Museum Collections Centre.