Blue plaque

A blue plaque is a permanent sign installed in a public place in the United Kingdom, and certain other countries and territories, to commemorate a link between that location and a famous person, event, or former building on the site, serving as a historical marker.

The term is used in the United Kingdom in two senses. It may be used narrowly and specifically to refer to the "official" scheme administered by English Heritage, and for much of its history restricted to sites within Greater London; or it may be used less formally to encompass a number of similar schemes administered by organisations throughout the UK. The plaques erected are made in a variety of designs, shapes, materials and colours: some are blue, others are not. However, the term "blue plaque" is often used informally to encompass all such schemes.