Since the Victorians improved the sewage system and the large-scale demise of industry along the Thames, water quality has steadily improved. Life has returned to the river and its banks. It has long been boasted that London has one of the cleanest urban rivers, supporting great quantities of bird-life and even has Salmon returning to the river to spawn.

There are many wildlife reserves on or near the upper tideway – (Wildfowl & Wetlands Trust at Barn Elms, Kew Heronry). Much of the wildlife in these reserves relies heavily on the river with its bountiful supplies of micro-organisms, insect-life and fish.

The obvious signs of the large sewage discharges of 2004 were the immediate and almost total devastation of the fish population. The remarkable aspect was the speed at which fish returned to repopulate the river after each event. It is not clear however, whether the recovery is complete across all species, and what the effects of the discharges are on the smaller scale fauna and flora of the river environment.

A pressing concern is the possible effects of larger or more frequent discharges, especially as this is predicted as a result of the current sewage and drainage system faced with increasing sewage input and possible climatic changes causing an increased level of rainfall.