Located on Windsor High Street next to the Guild Hall is a green hexagonal Penfold post box.

This broke the standard pattern and so in 1866 the Post Office again produced a standard letter box. This time the box was designed by J W Penfold and came in three sizes. Problems were encountered with some of the early designs however and modifications were made, such as the inclusion of downward-pointing shoots to help prevent letters being caught up in the cap of the box. The ‘Penfold’ letter box while not particularly a success operationally was very popular with many people.

As a standard box however it was not to survive. In 1879 a further standard box was produced. This time more of the earlier lessons were taken on board. The new standard box at last resembled the letter box that is today the iconic image of Britain – cylindrical with round cap and horizontal aperture under a protruding cap with front opening door and black painted base.

The Postal Museum Website explains how the Pillar Boxes went from red to green and back again.

Near to Windsor castle, situated next to a more usual red pillar box is a blue George V pillar box. The blue pillar box displays the history of ’special’ blue pillar boxes:

On 9th September 1911, Gustav Hamel took of from Hendon Aerodrome to inaugurate the first United Kingdom aerial post and landed in Shaw Farm meadow, Long Walk, Windsor.

The flight was organised to carry special mail celebrating the coronation of King George V.

Within a few years, Air mail services became well established and between 1930 and 1938, special blue pillar boxes were used for posting Air Letters.

This box is adjacent to the site of Windsor Post Office (1887 – 1966) where Air Mail was received from the United Kingdom aerial post.

Next to the two pillar boxes is a historic stamp vending machine.