There are over 115,000 letter boxes in the United Kingdom. At least one stands within 1/2 mile of 98% of the UK population!  They began to apear during the late 1840s,  introduced as a result of Postal Reform which introduced a universal, affordable postage rate. The oldest surviving letter box, still in use, is located in Holwell, near Sherborne in Dorset. It was erected during the reign of Queen Victoria in 1853.  The Post Office issued a set of stamps in October 2002, to celebrate the history of this much loved British icon!