The old Low Light in Clifford's Fort
The Low Light and The High Light were 'lined-up', one above the other, by vessels entering the river to avoid the notorious rocks known as 'The Black Middens'.
These were the first of two such pairs of fixed lights. Before that the lights were movable as the navigable channel moved. The wall was later painted black to avoid confusion with the 'new' Low Light, seen in the background.