Coal post
Introduction
The photograph on this page of Coal post by Bikeboy as part of the Geograph project.
The Geograph project started in 2005 with the aim of publishing, organising and preserving representative images for every square kilometre of Great Britain, Ireland and the Isle of Man.
There are currently over 7.5m images from over 14,400 individuals and you can help contribute to the project by visiting https://www.geograph.org.uk

Image: © Bikeboy Taken: 29 Mar 2013
There are a ring of these around London. See http://www.geograph.org.uk/photo/3368546 and http://www.geograph.org.uk/photo/3368543 for other examples. They mark positions where tax on coal and other commodities were taxed as they were brought into London. See http://en.wikipedia.org/wiki/Coal-tax_post for further information.