Lost River Bunker
History as always, appears to be pointless in recording. Seemingly so, as nothing of course can be found on this cave-like bunker. So here we go... perhaps it started off as a cave, was tunnelled out to create an air raid shelter (judging from the man-made excavation) and then later became a storage facility for the Metropolitan Water Supply - Sewerage and Drainage Department depot once located at the front of it.
Of course later on, it probably had people living in there, judging from the blackened roof and remains left behind.