You can never have enough.
via Diamond Geezer (probably... this sort of stuff usually originates on his blog.... ah yes.... here)
Underground Waterways and unexpected tunnels
The underground map is interesting.... it suggests the Northern Low-level sewer heads inland east of Tower Hill to meet the mid-level sewer at Stratford via Bow.
So where does the effluent of Docklands go? (And no... the answer is not that the effluent of Docklands is recycled here; that would be too extreme. They merely recycle the effluent of Westminster)