L = Lamp box

Lamp boxes were first introduced in 1896; a small letter box designed to be attached to lamp posts in locations such as London’s affluent squares and crescents to allow late-evening posting of correspondence. Being cheap to provide they soon became the box of choice for many rural areas where the volume of posting did not justify the expense of a pillar or wall box.
The Letter Box Study Group
2016-02-10T16:08:31+00:00
Lamp boxes were first introduced in 1896; a small letter box designed to be attached to lamp posts in locations such as London’s affluent squares and crescents to allow late-evening posting of correspondence. Being cheap to provide they soon became the box of choice for many rural areas where the volume of posting did not justify the expense of a pillar or wall box.