These two postboxes are in the market square in Cambridge.
It is unusual to see two postboxes side by side, but the placement of these two next to one another may be unique because they are father and daughter postboxes.
The one on the left is marked GR, which means it is from the reign of George VI.
The one on the right is marked ER, which means it is from the reign of the current monarch Elizabeth II, the daughter of George VI.
Photograph Works 