From Wikipaedia:
In 1653, the first post boxes are believed to have been installed in and around Paris.[1] By 1829, post boxes were in use throughout France.[2] The first public post boxes in Poland were installed in Warsaw in 1842.[3]
A post box originally installed in the wall of the Wakefield Post Office is dated 1809 and believed to be the oldest example in Britain.[4]It is now on display at the new Wakefield Museum.[5]
In the British Isles, the first red pillar post boxes were erected in Jersey in 1852.[6]Roadside wall boxes first appeared in 1857 as a cheaper alternative to pillar boxes, especially in rural districts. In 1853 the first pillar box in the United Kingdom was installed at Botchergate, Carlisle. In 1856, Richard Redgrave of the Department of Science and Art designed an ornate pillar box for use in London and other large cities. In 1859 the design was improved, and this became the first National Standard pillar box. Green was adopted as the standard colour for the early Victorian post boxes. Between 1866 and 1879 the hexagonal Penfold post box became the standard design for pillar boxes and it was during this period that red was first adopted as the standard colour. The first boxes to be painted red were in London in July 1874, although it would be nearly 10 years before all the boxes had been repainted.[7] In 2012 to celebrate Olympic gold medals for Team GB, selected boxes are painted gold. One has been vandalised briefly with graffiti.[8] One has been painted in the 'wrong' town.[9]
With pictures:
http://www.postalheritage.org.uk/explore/history/letterboxes/
