This cache is a nano hidden opposite a Victorian stink pipe. Made from cast iron and usually painted green or grey, these stink pipes are often mistaken for lamposts. Some stink pipes are fairly boring to look at but many feature the types of embellishments that Victorians were fond of e.g. fluted columns around the bottom, studded rings, roses etc.
Stink pipes were employed to vent gases from the underground sewers (some of them are still doing this). Stink pipes were a response the The Great Stink of 1858. For many years the Thames had been a dumping ground for all manner of human, animal and industrial waste; the scorching summer of 1858 heated up this sewage and almost brought London to a standstill. Something had to be done. Proper seweage systems were built with and these pipes provided ventilation.